US20090026481A1 - Nitride semiconductor light-emitting device and method of manufacturing nitride semiconductor light-emitting device - Google Patents

Nitride semiconductor light-emitting device and method of manufacturing nitride semiconductor light-emitting device Download PDF

Info

Publication number
US20090026481A1
US20090026481A1 US12/232,525 US23252508A US2009026481A1 US 20090026481 A1 US20090026481 A1 US 20090026481A1 US 23252508 A US23252508 A US 23252508A US 2009026481 A1 US2009026481 A1 US 2009026481A1
Authority
US
United States
Prior art keywords
film
light
nitride semiconductor
cavity
oxide film
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US12/232,525
Inventor
Takeshi Kamikawa
Yoshinobu Kawaguchi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sharp Corp
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US12/232,525 priority Critical patent/US20090026481A1/en
Assigned to SHARP KABUSHIKI KAISHA reassignment SHARP KABUSHIKI KAISHA ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KAMIKAWA, TAKESHI, KAWAGUCHI, YOSHINOBU
Publication of US20090026481A1 publication Critical patent/US20090026481A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/30—Structure or shape of the active region; Materials used for the active region
    • H01S5/34—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers
    • H01S5/343—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser
    • H01S5/34333—Structure or shape of the active region; Materials used for the active region comprising quantum well or superlattice structures, e.g. single quantum well [SQW] lasers, multiple quantum well [MQW] lasers or graded index separate confinement heterostructure [GRINSCH] lasers in AIIIBV compounds, e.g. AlGaAs-laser, InP-based laser with a well layer based on Ga(In)N or Ga(In)P, e.g. blue laser
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/02—Structural details or components not essential to laser action
    • H01S5/028—Coatings ; Treatment of the laser facets, e.g. etching, passivation layers or reflecting layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
    • H01S5/22—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure
    • H01S5/223—Buried stripe structure
    • H01S5/2231—Buried stripe structure with inner confining structure only between the active layer and the upper electrode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/0014—Measuring characteristics or properties thereof
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/20—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers
    • H01S5/22—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure
    • H01S5/2205—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure comprising special burying or current confinement layers
    • H01S5/2206—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure comprising special burying or current confinement layers based on III-V materials
    • H01S5/221—Structure or shape of the semiconductor body to guide the optical wave ; Confining structures perpendicular to the optical axis, e.g. index or gain guiding, stripe geometry, broad area lasers, gain tailoring, transverse or lateral reflectors, special cladding structures, MQW barrier reflection layers having a ridge or stripe structure comprising special burying or current confinement layers based on III-V materials containing aluminium

Definitions

  • the present invention relates to a nitride semiconductor light-emitting device and a method of manufacturing a nitride semiconductor light-emitting device.
  • an AR (Anti-Reflectance) coating film for attaining the reflectance of approximately 10% at the facet of the cavity with respect to the laser beams may be formed on a light-emitting facet of the cavity that should serve as a light-emitting portion of the nitride semiconductor laser device, and an HR (High-Reflectance) coating film for attaining the reflectance at approximately 80 to 100% with respect to the laser beams may be formed on a light-reflecting facet of the cavity (see, for example, Patent Document 1 (Japanese Patent Laying-Open No. 09-162496), Patent Document 2 (Japanese Patent Laying-Open No. 2002-237648), and Patent Document 3 (Japanese Patent Laying-Open No. 03-209895)).
  • the threshold value can be lowered by raising the reflectance at the light-emitting facet of the cavity with respect to the laser beams to thereby lower mirror loss.
  • a COD level optical output at the time when the light-emitting facet of the cavity is broken due to COD
  • a single layer of a silicon oxide film, an aluminum oxide film, a titanium oxide film, a tantalum oxide film, a zinc oxide film, or the like is formed as an AR coating film on the light-emitting facet of the cavity of the nitride semiconductor laser device, however, improvement in the reflectance at the light-emitting facet of the cavity has not been sufficient.
  • a multi-layer film formed of a stack of an aluminum oxide film and a silicon oxide film is formed as an AR coating film in contact with the light-emitting facet of the cavity, the COD level has been low.
  • optical density at the light-emitting facet of the cavity is increased when the reflectance at the light-emitting facet of the cavity is higher, it has been conventionally difficult to achieve higher reflectance at the light-emitting facet of the cavity while maintaining high COD level.
  • an object of the present invention is to provide a nitride semiconductor light-emitting device capable of achieving higher reflectance at a light-emitting facet of a cavity while maintaining a high COD level, as well as a method of manufacturing a nitride semiconductor light-emitting device.
  • the present invention is directed to a nitride semiconductor light-emitting device including a coating film and a reflectance control film successively formed on a light-emitting portion, the light-emitting portion being formed of a nitride semiconductor, the coating film being formed of an aluminum oxynitride film or an aluminum nitride film, and the reflectance control film being formed of an oxide film.
  • the reflectance control film is formed of a stack of an aluminum oxide film and a silicon oxide film.
  • oxygen content in the coating film is in a range from at least 0 atomic % to at most 35 atomic %.
  • the light-emitting portion has reflectance of at least 18% with respect to light emitted from the nitride semiconductor light-emitting device.
  • an aluminum oxide film and a stack of a silicon oxide film and a tantalum oxide film are successively formed on a light-reflection side.
  • an aluminum oxide film and a stack of a silicon nitride film and a silicon oxide film are successively formed on a light-reflection side.
  • the present invention is directed to a method of manufacturing a nitride semiconductor light-emitting device including a coating film and a reflectance control film successively formed on a light-emitting portion, and the method includes the steps of: forming the coating film formed of an aluminum oxynitride film or an aluminum nitride film on the light-emitting portion; and forming the reflectance control film formed of an oxide film on the coating film.
  • a stack of an aluminum oxide film and a silicon oxide film is preferably formed as the reflectance control film.
  • the coating film may be formed by using aluminum oxide as a target.
  • a nitride semiconductor light-emitting device capable of achieving higher reflectance at a light-emitting facet of a cavity while maintaining a high COD level, as well as a method of manufacturing a nitride semiconductor light-emitting device can be provided.
  • FIG. 1 is a schematic cross-sectional view of a preferred exemplary nitride semiconductor laser device representing a nitride semiconductor light-emitting device of the present invention.
  • FIG. 2 is a schematic side view of the nitride semiconductor laser device shown in FIG. 1 , in a direction of length of a cavity.
  • FIG. 3 is a schematic view of a configuration of an exemplary ECR sputtering film deposition apparatus.
  • FIG. 4 shows results of analysis by using AES, in a direction of thickness, of a composition of aluminum oxynitride separately fabricated under the conditions the same as those for a coating film in an embodiment of the present invention.
  • FIG. 5 shows results of theoretical calculation of reflectance spectrum at a light-emitting facet of the cavity of the nitride semiconductor laser device in the embodiment of the present invention.
  • FIG. 6 shows results of actual measurement of reflectance spectrum at the light-emitting facet of the cavity of the nitride semiconductor laser device in the embodiment of the present invention.
  • FIG. 7 shows results of examination of the COD level after aging, of the nitride semiconductor laser device in the embodiment of the present invention.
  • FIG. 8 shows results of examination of dependency on the COD level, of oxygen content in the coating film of the nitride semiconductor laser device in the embodiment of the present invention.
  • FIGS. 9A and 9B show results of theoretical calculation of reflectance spectrum at a light-emitting facet of a cavity of another exemplary nitride semiconductor laser device of the present invention
  • FIG. 10 shows results of examination of the COD level after aging, of a nitride semiconductor laser device according to a comparative example.
  • FIG. 1 is a schematic cross-sectional view of a preferred exemplary nitride semiconductor laser device representing a nitride semiconductor light-emitting device of the present invention.
  • a nitride semiconductor laser device 100 is structured such that, through epitaxial growth, an n-type buffer layer 102 composed of n-type GaN having a thickness of 0.2 ⁇ m, an n-type clad layer 103 composed of n-type Al 0.06 Ga 0.94 N having a thickness of 2.3 ⁇ m, an n-type guide layer 104 composed of n-type GaN having a thickness of 0.02 ⁇ m, a multiple quantum well active layer 105 constituted of a multiple quantum well layer composed of InGaN having a thickness of 4 nm and GaN having a thickness of 8 nm and a protection layer composed of GaN having a thickness of 70 nm, a p-type current blocking layer 106 composed of p-type Al 0.3 Ga 0.7 N having a thickness of
  • each layer has a composition ratio adjusted as appropriate and thus irrelevant to the essence of the present invention.
  • a wavelength of a laser beam lased from the nitride semiconductor laser device of the present embodiment can be adjusted as appropriate, for example, in a range from at least 370 nm to at most 470 nm, depending on the composition ratio of multiple quantum well active layer 105 . In the present embodiment, adjustment is made such that the laser beam at a wavelength of 405 nm is lased.
  • Nitride semiconductor laser device 100 is formed such that a stripe-shaped ridged stripe portion 111 extends in a direction of length of the cavity, by partially removing p-type clad layer 107 and p-type contact layer 108 .
  • ridged stripe portion 111 has a stripe width, for example, in a range from approximately 1.2 ⁇ m to 2.4 ⁇ m, typically approximately 1.5 ⁇ m. It is noted that the stripe width of ridged stripe portion 111 of nitride semiconductor laser device 100 is not limited as such. The stripe width may be set, for example, in a range from approximately 2 ⁇ m to 100 ⁇ m, so that nitride semiconductor laser device 100 is applicable also as a broad area type nitride semiconductor laser device used for illumination purposes.
  • a p electrode 110 formed as a stack of a Pd layer, an Mo layer, and an Au layer is provided on the surface of p-type contact layer 108
  • an insulating film 109 formed as a stack of an SiO 2 film and a TiO 2 film is provided under p electrode 110 , except for where ridged stripe portion 111 is formed.
  • an n electrode 112 formed as a stack of an Hf film and an Al film is formed on the surface of semiconductor substrate 101 opposite to where the above-described layers are stacked.
  • FIG. 2 is a schematic side view of nitride semiconductor laser device 100 shown in FIG. 1 , in a direction of length of the cavity.
  • a coating film 114 formed of an aluminum oxynitride film having a thickness of 6 nm is formed on a light-emitting facet of cavity 113 of nitride semiconductor laser device 100 , and an aluminum oxide film 115 having a thickness of 117 nm is formed on coating film 114 .
  • a silicon oxide film 122 having a thickness of 71 nm is formed on aluminum oxide film 115
  • an aluminum oxide film 116 having a thickness of 60 nm is formed on silicon oxide film 122 .
  • a reflectance control film 121 is formed of aluminum oxide film 115 , silicon oxide film 122 , and aluminum oxide film 116 .
  • coating film 114 has an index of refraction of 2.1 with respect to light of a wavelength of 400 nm
  • aluminum oxide film 115 has an index of refraction of 1.68 with respect to light of a wavelength of 400 nm.
  • silicon oxide film 122 has an index of refraction of 1.43 with respect to light of a wavelength of 400 nm
  • aluminum oxide film 116 has an index of refraction of 1.68 with respect to light of a wavelength of 400 nm. Accordingly, the reflectance at light-emitting facet of cavity 113 with respect to the laser beam of a wavelength of 405 nm lased from nitride semiconductor laser device 100 can be controlled to approximately 30%.
  • aluminum oxynitride film 118 has an index of refraction of 2.1 with respect to light of a wavelength of 400 nm
  • aluminum oxide film 119 has an index of refraction of 1.68 with respect to light of a wavelength of 400 nm.
  • the silicon oxide film constituting high-reflection film 120 has an index of refraction of 1.43 with respect to light of a wavelength of 400 nm
  • the titanium oxide film constituting high-reflection film 120 has an index of refraction of 2.4 with respect to light of a wavelength of 400 nm. Accordingly, the reflectance at light-reflecting facet of cavity 117 with respect to the laser beam of a wavelength of 405 nm lased from nitride semiconductor laser device 100 can be controlled to approximately 95%.
  • the reflectance of approximately 95% can be achieved.
  • an aluminum oxynitride film having a thickness of 6 nm and an aluminum oxide film having a thickness of 117 nm are successively formed on light-reflecting facet of cavity 117 of nitride semiconductor laser device 100 , and thereafter a stack formed by stacking 6 pairs of a silicon oxide film having a thickness of 71 nm and a tantalum oxide film having a thickness of 51 nm (starting from the silicon oxide film) is formed and an aluminum oxide film having a thickness of 120 nm is formed on an outermost surface, thus forming a multi-layer film.
  • the tantalum oxide film has an index of refraction of 2.0 with respect to light of a wavelength of 400 nm.
  • an aluminum oxynitride film having a thickness of 6 nm and an aluminum oxide film having a thickness of 117 nm are successively formed on light-reflecting facet of cavity 117 of nitride semiconductor laser device 100 , and thereafter a stack formed by stacking 7 pairs of a silicon nitride film having a thickness of 48 nm and a silicon oxide film having a thickness of 71 nm (starting from the silicon nitride film) is formed and a silicon oxide film having a thickness of 142 nm is formed on an outermost surface, thus forming a multi-layer film.
  • the silicon nitride film has an index of refraction of 2.1 with respect to light of a wavelength of 400 nm.
  • Coating film 114 , reflectance control film 121 , aluminum oxynitride film 118 , aluminum oxide film 119 , and high-reflection film 120 are formed on facet of cavity 113 and facet of cavity 117 of each sample, the sample being fabricated by successively stacking aforementioned nitride semiconductor layers such as a buffer layer on the semiconductor substrate described above, forming the ridged stripe portion, and thereafter cleaving a wafer where the insulating film, the p electrode and the n electrode are formed, to thereby expose cleavage planes, i.e., facet of cavity 113 and facet of cavity 117 .
  • facet of cavity 113 is preferably cleaned by heating to a temperature, for example, of at least 100° C. in a film deposition apparatus so as to remove an oxide film, an impurity and the like adhered to facet of cavity 113 , however, in the present invention, it is not essential.
  • facet of cavity 113 may be cleaned by irradiating facet of cavity 113 , for example, with argon or nitrogen plasma, however, in the present invention, it is not essential.
  • plasma irradiation while heating facet of cavity 113 may be adopted.
  • nitrogen plasma irradiation may follow argon plasma irradiation, or vice versa.
  • argon and nitrogen for example, a rare gas such as helium, neon, xenon, or krypton may be used.
  • Forming of coating film 114 and reflectance control film 121 to be formed on facet of cavity 113 is preferably carried out at a heated temperature, for example, in a range from at least 100° C. to at most 500° C., however, in the present invention, coating film 114 and reflectance control film 121 may be formed without heating.
  • Coating film 114 and reflectance control film 121 described above may be formed, for example, with ECR (Electron Cyclotron Resonance) sputtering which will be described below, however, they may be formed with other various sputtering methods or CVD (Chemical Vapor Deposition) or EB (Electron Beam) vapor deposition.
  • ECR Electro Cyclotron Resonance
  • CVD Chemical Vapor Deposition
  • EB Electrode
  • FIG. 3 is a schematic view of a configuration of an exemplary ECR sputtering film deposition apparatus.
  • the ECR sputtering film deposition apparatus includes a film deposition chamber 200 , a magnetic coil 203 , and a microwave introduction window 202 .
  • a gas inlet port 201 and a gas exhaust port 209 are provided, and an Al target 204 connected to an RF power supply 208 and a heater 205 are provided.
  • a sample carrier 207 is provided and a sample 206 is placed on sample carrier 207 .
  • Magnetic coil 203 is provided in order to produce magnetic field necessary for generating plasma, and RF power supply 208 is used for sputtering Al target 204 .
  • microwaves 210 are introduced into film deposition chamber 200 through microwave introduction window 202 .
  • Gaseous nitrogen is introduced into film deposition chamber 200 through gas inlet port 201 at a flow rate of 5.5 sccm, and gaseous oxygen is introduced at a flow rate of 1.0 sccm.
  • gaseous argon is introduced at a flow rate of 20.0 sccm. It is noted that the oxygen content in coating film 114 can be varied by varying a ratio between the gaseous nitrogen and the gaseous oxygen in growth chamber 200 .
  • RF power of 500 W is applied to Al target 204 and microwave power of 500 W necessary for generating plasma is applied, whereby coating film 114 composed of aluminum oxynitride having an index of refraction of 2.1 with respect to light of a wavelength of 400 nm can be formed at the film deposition rate of 1.7 angstrom/second.
  • contents of aluminum, nitrogen and oxygen (atomic %) forming coating film 114 can be measured, for example, with AES (Auger Electron Spectroscopy).
  • content of oxygen composing coating film 114 can be measured also with TEM-EDX (Transmission Electron Microscopy-Energy Dispersive X-ray Spectroscopy).
  • FIG. 4 shows results of analysis by using AES, in a direction of thickness, of a composition of aluminum oxynitride separately fabricated under the same conditions and with the same method as described above.
  • the contents of aluminum, oxygen and nitrogen, respectively, were obtained as based on an AES signal in intensity, with the sensitivity of a peak of each element considered.
  • aluminum, oxide and nitrogen together assume 100 atomic % and an element other than aluminum, oxygen and nitrogen, contained in a small amount, such as argon, is excluded therefrom.
  • the content of aluminum composing aluminum oxynitride is 34.8 atomic %
  • the content of oxygen is 3.8 atomic %
  • the content of nitrogen is 61.4 atomic %, with a substantially uniform composition in the direction of thickness. It should be noted that, although not shown in FIG. 4 , a negligible amount of argon was detected.
  • aluminum oxide film 115 is formed on coating film 114 with ECR sputtering.
  • aluminum oxide film 115 is fabricated, for example, as follows. Initially, in the ECR sputtering film deposition apparatus shown in FIG. 3 , after coating film 114 is formed, the gaseous oxygen is introduced into film deposition chamber 200 through gas inlet port 201 at a flow rate of 6.5 sccm. In addition, in order to efficiently generate plasma so as to increase a film deposition speed, the gaseous argon is introduced at a flow rate of 40 sccm.
  • silicon oxide film 122 is formed on aluminum oxide film 115 using ECR sputtering.
  • silicon oxide film 122 is fabricated, for example, as follows. Initially, in the ECR sputtering film deposition apparatus shown in FIG. 3 , Al target 204 is replaced with an Si target. After aluminum oxide film 115 is formed, the gaseous oxygen is introduced into film deposition chamber 200 through gas inlet port 201 at a flow rate of 7.5 sccm. In addition, in order to efficiently generate plasma so as to increase a film deposition speed, the gaseous argon is introduced at a flow rate of 20 sccm.
  • aluminum oxide film 116 is formed on silicon oxide film 122 using ECR sputtering.
  • aluminum oxide film 116 is fabricated, for example, as follows. Initially, in the ECR sputtering film deposition apparatus shown in FIG. 3 , the Si target used for forming silicon oxide film 122 is replaced with the Al target. Then, the gaseous oxygen is introduced into film deposition chamber 200 through gas inlet port 201 at a flow rate of 6.5 sccm. In addition, in order to efficiently generate plasma so as to increase a film deposition speed, the gaseous argon is introduced at a flow rate of 40 sccm.
  • reflectance control film 121 constituted of aluminum oxide film 115 , silicon oxide film 122 , and aluminum oxide film 116 is formed on coating film 114 .
  • Aluminum oxynitride film 118 , aluminum oxide film 119 , and high-reflection film 120 on light-reflecting facet of cavity 117 can also be formed with ECR sputtering, as in the case of coating film 114 and the like.
  • cleaning through heating and/or cleaning with plasma irradiation is also performed before forming these films. It is noted here that deterioration of the light-emitting portion gives rise to a problem on the light-emitting side where optical density is great, whereas deterioration does not cause a problem on the light-reflection side in many cases because optical density is smaller on the light-reflection side than on the light-emitting side.
  • aluminum oxynitride film 118 having a thickness of 6 nm is formed on light-reflecting facet of cavity 117 , however, aluminum oxynitride film 118 may have a greater thickness, for example, of 50 nm.
  • heat treatment may be performed.
  • removal of moisture contained in the films or improvement in film quality through heat treatment can be expected.
  • coating film 114 , aluminum oxide film 115 , silicon oxide film 122 , and aluminum oxide film 116 are successively formed on light-emitting facet of cavity 113 of the sample, and aluminum oxynitride film 118 , aluminum oxide film 119 , and high-reflection film 120 are successively formed on light-reflecting facet of cavity 117 . Thereafter, the sample is divided into chips, to thereby obtain nitride semiconductor laser devices 100 shown in FIG. 1 .
  • FIG. 5 shows results of theoretical calculation of reflectance spectrum at light-emitting facet of cavity 113 of nitride semiconductor laser device 100 structured as described above. It can be seen from FIG. 5 that high reflectance of approximately 30% with respect to light of a wavelength of 405 nm can be obtained at light-emitting facet of cavity 113 of nitride semiconductor laser device 100 .
  • FIG. 6 shows results of actual measurement of reflectance spectrum at light-emitting facet of cavity 113 of nitride semiconductor laser device 100 structured as described above. It can be seen from FIG. 6 that high reflectance of approximately 30% with respect to light of a wavelength of 405 nm can be obtained at light-emitting facet of cavity 113 of nitride semiconductor laser device 100 , which is substantially the same as the theoretical calculation result shown in FIG. 5 .
  • the theoretical calculation result of reflectance spectrum shown in FIG. 5 was obtained by theoretical calculation based on measurement of a thickness and an index of refraction with respect to light of a wavelength of 400 nm n, of each layer forming nitride semiconductor laser device 100 .
  • the thickness and the index of refraction with respect to light of a wavelength of 400 nm of each layer constituting nitride semiconductor laser device 100 were found using ellipsometry.
  • the actual reflectance spectrum shown in FIG. 6 was found based on spectroscopy of white light and measurement of reflectance with respect to light of each wavelength.
  • the COD level after aging (80° C., CW drive, optical output of 40 mW, 300 hours) of nitride semiconductor laser device 100 described above was examined, and the results are as shown in FIG. 7 . As shown in FIG. 7 , it was found that the COD level after aging of nitride semiconductor laser device 100 was very high around 350 to 400 mW.
  • a nitride semiconductor laser device according to a comparative example having a structure the same as nitride semiconductor laser device 100 except that reflectance control film 121 as above was directly formed on light-emitting facet of cavity 113 without coating film 114 , was fabricated. Then, the COD level after aging (80° C., CW drive, optical output of 40 mW, 300 hours) of the nitride semiconductor laser device according to the comparative example was examined. The results are as shown in FIG. 10 . As shown in FIG. 10 , it was found that the COD level after aging of the nitride semiconductor laser device according to the comparative example was approximately 200 to 250 mW, which is significantly lower than that of nitride semiconductor laser device 100 described above.
  • the reason why the COD level after aging of nitride semiconductor laser device 100 was thus higher than that of the nitride semiconductor laser device according to the comparative example may be because the number of nonradiative centers at an interface between light-emitting facet of cavity 113 and coating film 114 decreased as a result of formation of coating film 114 on light-emitting facet of cavity 113 and/or because close contact between light-emitting facet of cavity 113 and coating film 114 was attained.
  • the oxygen content in coating film 114 was varied from O atomic % to 50 atomic %, and the COD level of nitride semiconductor laser device 100 after aging for 300 hours (300 hours, 80° C., optical output of 100 mW, CW drive) was measured.
  • the oxygen content in coating film 114 is varied, the content of aluminum (atomic %) in coating film 114 hardly varies and the content of nitrogen (atomic %) decreases in correspondence with increase in the content of oxygen (atomic %), because both of oxygen and nitrogen can basically bond to aluminum.
  • the oxygen content in coating film 114 is in a range from at least 0 atomic % to at most 35 atomic %, in particular when the oxygen content in coating film 114 is in a range from at least 2 atomic % to at most 30 atomic %, the COD level tends to be very high at 300 mW or greater. Therefore, the oxygen content in coating film 114 formed on light-emitting facet of cavity 113 is preferably in a range from at least 0 atomic % to at most 35 atomic % and more preferably in a range from at least 2 atomic % to at most 30 atomic %, in which case the COD level after aging tends to improve.
  • coating film 114 is formed of an aluminum nitride film, and when the oxygen content is greater than 0 atomic %, coating film 114 is formed of an aluminum oxynitride film.
  • the reason why the COD level can be high when the oxygen content in coating film 114 formed on light-emitting facet of cavity 113 is in a range from at least 0 atomic % to at most 35 atomic % may be because close contact between facet of cavity 113 formed of a nitride semiconductor and coating film 114 is improved and generation of nonradiative recombination level due to oxidation of facet of cavity 113 does not affect the COD level.
  • the COD level is slightly lower. This may be because aluminum nitride composing coating film 114 has large internal stress and contact between facet of cavity 113 and coating film 114 becomes weaker.
  • the present inventors have found that the COD level improves when silicon nitride is contained in coating film 114 composed of aluminum nitride. This may be because silicon nitride mitigates the internal stress of aluminum nitride.
  • the oxygen content in coating film 114 is greater than 35 atomic %, it is considered that a part of facet of cavity 113 formed of a nitride semiconductor is oxidized by oxygen contained in coating film 114 and such oxidation results in nonradiative recombination level, which has led to lower COD level.
  • FIG. 9A shows results of theoretical calculation of reflectance spectrum at light-emitting facet of cavity 113 of another exemplary nitride semiconductor laser device, that is structured similarly to nitride semiconductor laser device 100 described above except that coating film 114 formed of an aluminum nitride film having a thickness of 24 nm, a silicon oxide film having a thickness of 64 nm, an aluminum nitride film having a thickness of 24 nm, and an aluminum oxide film having a thickness of 24 nm are successively formed on light-emitting facet of cavity 113 .
  • the aluminum nitride film has the index of refraction of 2.1 with respect to light of a wavelength of 400 nm
  • the silicon oxide film has the index of refraction of 1.43 with respect to light of a wavelength of 400 nm
  • the aluminum oxide film has the index of refraction of 1.68 with respect to light of a wavelength of 400 nm.
  • FIG. 9B shows results of theoretical calculation of reflectance spectrum at light-emitting facet of cavity 113 of another exemplary nitride semiconductor laser device, that is structured similarly to nitride semiconductor laser device 100 described above except that coating film 114 formed of an aluminum nitride film having a thickness of 3 nm, an aluminum oxide film having a thickness of 117 nm, a silicon oxide film having a thickness of 71 nm, an aluminum oxide film having a thickness of 60 nm, a silicon oxide film having a thickness of 71 nm, and an aluminum oxide film having a thickness of 60 nm are successively formed on light-emitting facet of cavity 113 .
  • the aluminum nitride film has the index of refraction of 2.1 with respect to light of a wavelength of 400 nm
  • the aluminum oxide film has the index of refraction of 1.68 with respect to light of a wavelength of 400 nm
  • the silicon oxide film has the index of refraction of 1.43 with respect to light of a wavelength of 400 nm.
  • the reflectance can be controlled by varying film structure on light-emitting facet of cavity 113 .
  • aluminum oxynitride discussed in the present invention may take any form in the present invention; aluminum oxide may be mixed in AlN, crystals of aluminum oxynitride may be present in AlN, or aluminum oxide and aluminum oxynitride may be present in AlN.
  • coating film 114 has a thickness of at least 1 nm. If coating film 114 has a thickness less than 1 nm, it becomes difficult to control the thickness of coating film 114 , and coating film 114 may not be formed on light-emitting facet of cavity 113 . On the other hand, even when the thickness of coating film 114 is too large, it is assumed that the effect of the present invention is not impaired, although internal stress of coating film 114 may give rise to a problem.
  • coating film 114 preferably has a thickness in a range from at least 3 nm to at most 50 nm.
  • the COD level of nitride semiconductor laser device 100 described above is significantly affected by coating film 114 on light-emitting facet of cavity 113 , but not much affected by reflectance control film 121 on coating film 114 . Therefore, in the present invention, reflectance control film 121 can be designed relatively freely, taking into consideration only the reflectance at light-emitting facet of cavity 113 , and hence the degree of freedom in design remarkably improves.
  • coating film 114 may also be formed, for example, with reactive sputtering, by providing a target composed of aluminum oxide in the film deposition chamber and introducing solely gaseous nitrogen into the film deposition chamber. If such a target composed of aluminum oxide is employed, the aluminum oxynitride film can be formed without intentionally introducing gaseous oxygen into the film deposition chamber.
  • coating film 114 formed of an aluminum oxynitride film as aluminum is highly prone to oxidation, control and reproduction of a composition of oxynitride low in oxygen content tends to be difficult when gaseous oxygen is introduced in the film deposition chamber.
  • the oxygen content in the aluminum oxynitride film can be varied also by varying film deposition conditions such as a degree of vacuum and/or a film deposition temperature in the film deposition chamber, whereby the composition of the aluminum oxynitride film can be varied. It is noted that a smaller degree of vacuum in the film deposition chamber leads to a result that an oxide is more readily taken into the aluminum oxynitride film, while a higher film deposition temperature leads to a result that an oxide is less likely to be taken into the aluminum oxynitride film.
  • film is deposited with sputtering using a target composed of Al (Al target) with the introduction of gaseous argon and gaseous nitrogen into the film deposition chamber after an inner wall of the film deposition chamber is oxidized or aluminum oxide is formed on the inner wall of the film deposition chamber, the inner wall of the film deposition chamber has oxygen departed because of plasma, and therefore, coating film 114 formed of the aluminum oxynitride film can be formed.
  • nitride semiconductor mainly composed of (at least 50 mass % of the total) AlInGaN (a compound of at least one group III element selected from the group of aluminum, indium and gallium and nitrogen representing group V elements) may be employed as the nitride semiconductor.
  • reflectance control film 121 is not particularly limited provided that it is formed of an oxide. Among others, however, a stack of an aluminum oxide film and a silicon oxide film is preferably used as reflectance control film 121 . If reflectance control film 121 is formed of the stack of the aluminum oxide film and the silicon oxide film, fluctuation in the reflectance at light-emitting facet of cavity 113 with respect to fluctuation in the thicknesses of respective films constituting reflectance control film 121 is small, and therefore, the reflectance can be reproduced with excellent controllability. In the present invention, it is noted that the stack of the aluminum oxide film and the silicon oxide film constituting reflectance control film 121 may be formed in such a manner that at least one aluminum oxide film and at least one silicon oxide film are alternately stacked.
  • the reflectance at light-emitting facet of cavity 113 with respect to laser beams (laser beam of a wavelength, for example, in a range from at least 370 nm to at most 470 nm) lased from nitride semiconductor laser device 100 is preferably at least 18%, more preferably at least 30%, and further preferably at least 40%.
  • the reflectance at light-emitting facet of cavity 113 is 18% or greater, generally, optical density at facet of cavity 113 is increased and it is less likely that high COD level is obtained.
  • the coating film formed of the aluminum oxynitride film or the aluminum nitride film is formed on facet of cavity 113 , it is likely that high COD level is obtained.
  • the reflectance at light-emitting facet of cavity 113 is 30% or greater, in particular 40% or greater, fluctuation in the reflectance with respect to thickness of each film constituting reflectance control film 121 can be made smaller by forming reflectance control film 121 with the stack of the aluminum oxide film and the silicon oxide film. Thus, it is likely that yield is improved.
  • the present invention is suitably used, for example, for a nitride semiconductor light-emitting device such as a nitride semiconductor laser device lasing at a wavelength in ultraviolet to green range, a nitride semiconductor laser device of a broad area type having a stripe of several tens ⁇ m in width and used for high-output applications, a nitride semiconductor light-emitting diode device lasing at a wavelength in ultraviolet to red range, or the like.
  • a nitride semiconductor light-emitting device such as a nitride semiconductor laser device lasing at a wavelength in ultraviolet to green range, a nitride semiconductor laser device of a broad area type having a stripe of several tens ⁇ m in width and used for high-output applications, a nitride semiconductor light-emitting diode device lasing at a wavelength in ultraviolet to red range, or the like.

Abstract

A nitride semiconductor light-emitting device including a coating film and a reflectance control film successively formed on a light-emitting portion, in which the light-emitting portion is formed of a nitride semiconductor, the coating film is formed of an aluminum oxynitride film or an aluminum nitride film, and the reflectance control film is formed of an oxide film, as well as a method of manufacturing the nitride semiconductor light-emitting device are provided.

Description

  • This nonprovisional application is based on Japanese Patent Applications Nos. 2006-119500 and 2007-077362 filed with the Japan Patent Office on Apr. 24, 2006 and Mar. 23, 2007, respectively, the entire contents of which are hereby incorporated by reference.
    • FIELD OF THE INVENTION
  • The present invention relates to a nitride semiconductor light-emitting device and a method of manufacturing a nitride semiconductor light-emitting device.
    • DESCRIPTION OF THE BACKGROUND ART
  • In a nitride semiconductor laser device representing nitride semiconductor light-emitting devices, in order to control reflectance at a facet of a cavity with respect to laser beams, an AR (Anti-Reflectance) coating film for attaining the reflectance of approximately 10% at the facet of the cavity with respect to the laser beams may be formed on a light-emitting facet of the cavity that should serve as a light-emitting portion of the nitride semiconductor laser device, and an HR (High-Reflectance) coating film for attaining the reflectance at approximately 80 to 100% with respect to the laser beams may be formed on a light-reflecting facet of the cavity (see, for example, Patent Document 1 (Japanese Patent Laying-Open No. 09-162496), Patent Document 2 (Japanese Patent Laying-Open No. 2002-237648), and Patent Document 3 (Japanese Patent Laying-Open No. 03-209895)).
    • SUMMARY OF THE INVENTION
  • Here, in the nitride semiconductor laser device, the threshold value can be lowered by raising the reflectance at the light-emitting facet of the cavity with respect to the laser beams to thereby lower mirror loss. Meanwhile, as the light-emitting facet of the cavity of the nitride semiconductor laser device may be broken due to COD (Catastrophic Optical Damage), a COD level (optical output at the time when the light-emitting facet of the cavity is broken due to COD) should be raised.
  • If a single layer of a silicon oxide film, an aluminum oxide film, a titanium oxide film, a tantalum oxide film, a zinc oxide film, or the like is formed as an AR coating film on the light-emitting facet of the cavity of the nitride semiconductor laser device, however, improvement in the reflectance at the light-emitting facet of the cavity has not been sufficient. Alternatively, if a multi-layer film formed of a stack of an aluminum oxide film and a silicon oxide film is formed as an AR coating film in contact with the light-emitting facet of the cavity, the COD level has been low.
  • Moreover, as optical density at the light-emitting facet of the cavity is increased when the reflectance at the light-emitting facet of the cavity is higher, it has been conventionally difficult to achieve higher reflectance at the light-emitting facet of the cavity while maintaining high COD level.
  • From the foregoing, an object of the present invention is to provide a nitride semiconductor light-emitting device capable of achieving higher reflectance at a light-emitting facet of a cavity while maintaining a high COD level, as well as a method of manufacturing a nitride semiconductor light-emitting device.
  • The present invention is directed to a nitride semiconductor light-emitting device including a coating film and a reflectance control film successively formed on a light-emitting portion, the light-emitting portion being formed of a nitride semiconductor, the coating film being formed of an aluminum oxynitride film or an aluminum nitride film, and the reflectance control film being formed of an oxide film.
  • In addition, preferably, in the nitride semiconductor light-emitting device according to the present invention, the reflectance control film is formed of a stack of an aluminum oxide film and a silicon oxide film.
  • In addition, preferably, in the nitride semiconductor light-emitting device according to the present invention, oxygen content in the coating film is in a range from at least 0 atomic % to at most 35 atomic %.
  • In addition, preferably, in the nitride semiconductor light-emitting device according to the present invention, the light-emitting portion has reflectance of at least 18% with respect to light emitted from the nitride semiconductor light-emitting device.
  • In addition, preferably, in the nitride semiconductor light-emitting device according to the present invention, an aluminum oxide film and a stack of a silicon oxide film and a tantalum oxide film are successively formed on a light-reflection side.
  • In addition, preferably, in the nitride semiconductor light-emitting device according to the present invention, an aluminum oxide film and a stack of a silicon nitride film and a silicon oxide film are successively formed on a light-reflection side.
  • Moreover, the present invention is directed to a method of manufacturing a nitride semiconductor light-emitting device including a coating film and a reflectance control film successively formed on a light-emitting portion, and the method includes the steps of: forming the coating film formed of an aluminum oxynitride film or an aluminum nitride film on the light-emitting portion; and forming the reflectance control film formed of an oxide film on the coating film.
  • In the method of manufacturing a nitride semiconductor light-emitting device according to the present invention, a stack of an aluminum oxide film and a silicon oxide film is preferably formed as the reflectance control film.
  • In addition, in the method of manufacturing a nitride semiconductor light-emitting device according to the present invention, if the coating film is formed of an aluminum oxynitride film, the coating film may be formed by using aluminum oxide as a target.
  • According to the present invention, a nitride semiconductor light-emitting device capable of achieving higher reflectance at a light-emitting facet of a cavity while maintaining a high COD level, as well as a method of manufacturing a nitride semiconductor light-emitting device can be provided.
  • The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a schematic cross-sectional view of a preferred exemplary nitride semiconductor laser device representing a nitride semiconductor light-emitting device of the present invention.
  • FIG. 2 is a schematic side view of the nitride semiconductor laser device shown in FIG. 1, in a direction of length of a cavity.
  • FIG. 3 is a schematic view of a configuration of an exemplary ECR sputtering film deposition apparatus.
  • FIG. 4 shows results of analysis by using AES, in a direction of thickness, of a composition of aluminum oxynitride separately fabricated under the conditions the same as those for a coating film in an embodiment of the present invention.
  • FIG. 5 shows results of theoretical calculation of reflectance spectrum at a light-emitting facet of the cavity of the nitride semiconductor laser device in the embodiment of the present invention.
  • FIG. 6 shows results of actual measurement of reflectance spectrum at the light-emitting facet of the cavity of the nitride semiconductor laser device in the embodiment of the present invention.
  • FIG. 7 shows results of examination of the COD level after aging, of the nitride semiconductor laser device in the embodiment of the present invention.
  • FIG. 8 shows results of examination of dependency on the COD level, of oxygen content in the coating film of the nitride semiconductor laser device in the embodiment of the present invention.
  • FIGS. 9A and 9B show results of theoretical calculation of reflectance spectrum at a light-emitting facet of a cavity of another exemplary nitride semiconductor laser device of the present invention
  • FIG. 10 shows results of examination of the COD level after aging, of a nitride semiconductor laser device according to a comparative example.
    •  DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • An embodiment of the present invention will be described hereinafter. In the drawings of the present invention, it is noted that the same reference characters represent the same or corresponding elements.
  • FIG. 1 is a schematic cross-sectional view of a preferred exemplary nitride semiconductor laser device representing a nitride semiconductor light-emitting device of the present invention. Here, a nitride semiconductor laser device 100 is structured such that, through epitaxial growth, an n-type buffer layer 102 composed of n-type GaN having a thickness of 0.2 μm, an n-type clad layer 103 composed of n-type Al0.06Ga0.94N having a thickness of 2.3 μm, an n-type guide layer 104 composed of n-type GaN having a thickness of 0.02 μm, a multiple quantum well active layer 105 constituted of a multiple quantum well layer composed of InGaN having a thickness of 4 nm and GaN having a thickness of 8 nm and a protection layer composed of GaN having a thickness of 70 nm, a p-type current blocking layer 106 composed of p-type Al0.3Ga0.7N having a thickness of 20 nm, a p-type clad layer 107 composed of p-type Al0.05Ga0.95N having a thickness of 0.5 μm, and a p-type contact layer 108 composed of p-type GaN having a thickness of 0.1 μm are successively stacked on a semiconductor substrate 101 composed of n-type GaN.
  • It should be noted that each layer has a composition ratio adjusted as appropriate and thus irrelevant to the essence of the present invention. In addition, a wavelength of a laser beam lased from the nitride semiconductor laser device of the present embodiment can be adjusted as appropriate, for example, in a range from at least 370 nm to at most 470 nm, depending on the composition ratio of multiple quantum well active layer 105. In the present embodiment, adjustment is made such that the laser beam at a wavelength of 405 nm is lased.
  • Nitride semiconductor laser device 100 is formed such that a stripe-shaped ridged stripe portion 111 extends in a direction of length of the cavity, by partially removing p-type clad layer 107 and p-type contact layer 108. Here, ridged stripe portion 111 has a stripe width, for example, in a range from approximately 1.2 μm to 2.4 μm, typically approximately 1.5 μm. It is noted that the stripe width of ridged stripe portion 111 of nitride semiconductor laser device 100 is not limited as such. The stripe width may be set, for example, in a range from approximately 2 μm to 100 μm, so that nitride semiconductor laser device 100 is applicable also as a broad area type nitride semiconductor laser device used for illumination purposes.
  • Moreover, a p electrode 110 formed as a stack of a Pd layer, an Mo layer, and an Au layer is provided on the surface of p-type contact layer 108, and an insulating film 109 formed as a stack of an SiO2 film and a TiO2 film is provided under p electrode 110, except for where ridged stripe portion 111 is formed. Further, an n electrode 112 formed as a stack of an Hf film and an Al film is formed on the surface of semiconductor substrate 101 opposite to where the above-described layers are stacked.
  • FIG. 2 is a schematic side view of nitride semiconductor laser device 100 shown in FIG. 1, in a direction of length of the cavity. Here, a coating film 114 formed of an aluminum oxynitride film having a thickness of 6 nm is formed on a light-emitting facet of cavity 113 of nitride semiconductor laser device 100, and an aluminum oxide film 115 having a thickness of 117 nm is formed on coating film 114. In addition, a silicon oxide film 122 having a thickness of 71 nm is formed on aluminum oxide film 115, and an aluminum oxide film 116 having a thickness of 60 nm is formed on silicon oxide film 122. Here, in the present embodiment, a reflectance control film 121 is formed of aluminum oxide film 115, silicon oxide film 122, and aluminum oxide film 116. Here, coating film 114 has an index of refraction of 2.1 with respect to light of a wavelength of 400 nm, and aluminum oxide film 115 has an index of refraction of 1.68 with respect to light of a wavelength of 400 nm. In addition, silicon oxide film 122 has an index of refraction of 1.43 with respect to light of a wavelength of 400 nm, and aluminum oxide film 116 has an index of refraction of 1.68 with respect to light of a wavelength of 400 nm. Accordingly, the reflectance at light-emitting facet of cavity 113 with respect to the laser beam of a wavelength of 405 nm lased from nitride semiconductor laser device 100 can be controlled to approximately 30%.
  • Meanwhile, on a light-reflecting facet of cavity 117 of nitride semiconductor laser device 100, an aluminum oxynitride film 118 having a thickness of 6 nm, an aluminum oxide film 119 having a thickness of 117 nm, and a high-reflection film 120 that is formed by stacking four pairs of a silicon oxide film having a thickness of 71 nm and a titanium oxide film having a thickness of 46 nm (starting from the silicon oxide film) and thereafter stacking a silicon oxide film having a thickness of 142 nm on an outermost surface are successively formed. Here, aluminum oxynitride film 118 has an index of refraction of 2.1 with respect to light of a wavelength of 400 nm, and aluminum oxide film 119 has an index of refraction of 1.68 with respect to light of a wavelength of 400 nm. Moreover, the silicon oxide film constituting high-reflection film 120 has an index of refraction of 1.43 with respect to light of a wavelength of 400 nm, and the titanium oxide film constituting high-reflection film 120 has an index of refraction of 2.4 with respect to light of a wavelength of 400 nm. Accordingly, the reflectance at light-reflecting facet of cavity 117 with respect to the laser beam of a wavelength of 405 nm lased from nitride semiconductor laser device 100 can be controlled to approximately 95%.
  • Alternatively, by forming a plurality of films different in indices of refraction other than the films structured as described above on light-reflecting facet of cavity 117 of nitride semiconductor laser device 100, the reflectance of approximately 95% can be achieved. For example, an aluminum oxynitride film having a thickness of 6 nm and an aluminum oxide film having a thickness of 117 nm are successively formed on light-reflecting facet of cavity 117 of nitride semiconductor laser device 100, and thereafter a stack formed by stacking 6 pairs of a silicon oxide film having a thickness of 71 nm and a tantalum oxide film having a thickness of 51 nm (starting from the silicon oxide film) is formed and an aluminum oxide film having a thickness of 120 nm is formed on an outermost surface, thus forming a multi-layer film. Here, the tantalum oxide film has an index of refraction of 2.0 with respect to light of a wavelength of 400 nm.
  • Alternatively, an aluminum oxynitride film having a thickness of 6 nm and an aluminum oxide film having a thickness of 117 nm are successively formed on light-reflecting facet of cavity 117 of nitride semiconductor laser device 100, and thereafter a stack formed by stacking 7 pairs of a silicon nitride film having a thickness of 48 nm and a silicon oxide film having a thickness of 71 nm (starting from the silicon nitride film) is formed and a silicon oxide film having a thickness of 142 nm is formed on an outermost surface, thus forming a multi-layer film. Here, the silicon nitride film has an index of refraction of 2.1 with respect to light of a wavelength of 400 nm.
  • Coating film 114, reflectance control film 121, aluminum oxynitride film 118, aluminum oxide film 119, and high-reflection film 120 are formed on facet of cavity 113 and facet of cavity 117 of each sample, the sample being fabricated by successively stacking aforementioned nitride semiconductor layers such as a buffer layer on the semiconductor substrate described above, forming the ridged stripe portion, and thereafter cleaving a wafer where the insulating film, the p electrode and the n electrode are formed, to thereby expose cleavage planes, i.e., facet of cavity 113 and facet of cavity 117.
  • Prior to forming coating film 114 and reflectance control film 121 described above, facet of cavity 113 is preferably cleaned by heating to a temperature, for example, of at least 100° C. in a film deposition apparatus so as to remove an oxide film, an impurity and the like adhered to facet of cavity 113, however, in the present invention, it is not essential. Alternatively, facet of cavity 113 may be cleaned by irradiating facet of cavity 113, for example, with argon or nitrogen plasma, however, in the present invention, it is not essential. Alternatively, plasma irradiation while heating facet of cavity 113 may be adopted. In plasma irradiation described above, for example, nitrogen plasma irradiation may follow argon plasma irradiation, or vice versa. Other than argon and nitrogen, for example, a rare gas such as helium, neon, xenon, or krypton may be used. Forming of coating film 114 and reflectance control film 121 to be formed on facet of cavity 113 is preferably carried out at a heated temperature, for example, in a range from at least 100° C. to at most 500° C., however, in the present invention, coating film 114 and reflectance control film 121 may be formed without heating.
  • Coating film 114 and reflectance control film 121 described above may be formed, for example, with ECR (Electron Cyclotron Resonance) sputtering which will be described below, however, they may be formed with other various sputtering methods or CVD (Chemical Vapor Deposition) or EB (Electron Beam) vapor deposition.
  • FIG. 3 is a schematic view of a configuration of an exemplary ECR sputtering film deposition apparatus. Here, the ECR sputtering film deposition apparatus includes a film deposition chamber 200, a magnetic coil 203, and a microwave introduction window 202. In film deposition chamber 200, a gas inlet port 201 and a gas exhaust port 209 are provided, and an Al target 204 connected to an RF power supply 208 and a heater 205 are provided. In addition, in film deposition chamber 200, a sample carrier 207 is provided and a sample 206 is placed on sample carrier 207. Magnetic coil 203 is provided in order to produce magnetic field necessary for generating plasma, and RF power supply 208 is used for sputtering Al target 204. In addition, microwaves 210 are introduced into film deposition chamber 200 through microwave introduction window 202.
  • Gaseous nitrogen is introduced into film deposition chamber 200 through gas inlet port 201 at a flow rate of 5.5 sccm, and gaseous oxygen is introduced at a flow rate of 1.0 sccm. In addition, in order to efficiently generate plasma so as to increase a film deposition speed, gaseous argon is introduced at a flow rate of 20.0 sccm. It is noted that the oxygen content in coating film 114 can be varied by varying a ratio between the gaseous nitrogen and the gaseous oxygen in growth chamber 200. Moreover, in order to sputter Al target 204, RF power of 500 W is applied to Al target 204 and microwave power of 500 W necessary for generating plasma is applied, whereby coating film 114 composed of aluminum oxynitride having an index of refraction of 2.1 with respect to light of a wavelength of 400 nm can be formed at the film deposition rate of 1.7 angstrom/second.
  • It is noted that contents of aluminum, nitrogen and oxygen (atomic %) forming coating film 114 can be measured, for example, with AES (Auger Electron Spectroscopy). Alternatively, content of oxygen composing coating film 114 can be measured also with TEM-EDX (Transmission Electron Microscopy-Energy Dispersive X-ray Spectroscopy).
  • FIG. 4 shows results of analysis by using AES, in a direction of thickness, of a composition of aluminum oxynitride separately fabricated under the same conditions and with the same method as described above. The contents of aluminum, oxygen and nitrogen, respectively, were obtained as based on an AES signal in intensity, with the sensitivity of a peak of each element considered. Herein, aluminum, oxide and nitrogen together assume 100 atomic % and an element other than aluminum, oxygen and nitrogen, contained in a small amount, such as argon, is excluded therefrom.
  • As shown in FIG. 4, it can be seen that the content of aluminum composing aluminum oxynitride is 34.8 atomic %, the content of oxygen is 3.8 atomic %, and the content of nitrogen is 61.4 atomic %, with a substantially uniform composition in the direction of thickness. It should be noted that, although not shown in FIG. 4, a negligible amount of argon was detected.
  • Thereafter, aluminum oxide film 115 is formed on coating film 114 with ECR sputtering. Here, aluminum oxide film 115 is fabricated, for example, as follows. Initially, in the ECR sputtering film deposition apparatus shown in FIG. 3, after coating film 114 is formed, the gaseous oxygen is introduced into film deposition chamber 200 through gas inlet port 201 at a flow rate of 6.5 sccm. In addition, in order to efficiently generate plasma so as to increase a film deposition speed, the gaseous argon is introduced at a flow rate of 40 sccm. Then, in order to sputter Al target 204, RF power of 500 W is applied to Al target 204 and microwave power of 500 W necessary for generating plasma is applied, whereby aluminum oxide film 115 having an index of refraction of 1.68 with respect to light of a wavelength of 400 nm is formed at the film deposition rate of 20 nm/second.
  • In succession, silicon oxide film 122 is formed on aluminum oxide film 115 using ECR sputtering. Here, silicon oxide film 122 is fabricated, for example, as follows. Initially, in the ECR sputtering film deposition apparatus shown in FIG. 3, Al target 204 is replaced with an Si target. After aluminum oxide film 115 is formed, the gaseous oxygen is introduced into film deposition chamber 200 through gas inlet port 201 at a flow rate of 7.5 sccm. In addition, in order to efficiently generate plasma so as to increase a film deposition speed, the gaseous argon is introduced at a flow rate of 20 sccm. Then, in order to sputter the Si target, RF power of 500 W is applied to the Si target and microwave power of 500 W necessary for generating plasma is applied, whereby silicon oxide film 122 having an index of refraction of 1.43 with respect to light of a wavelength of 400 nm is formed at the film deposition rate of 20 nm/second.
  • Thereafter, aluminum oxide film 116 is formed on silicon oxide film 122 using ECR sputtering. Here, aluminum oxide film 116 is fabricated, for example, as follows. Initially, in the ECR sputtering film deposition apparatus shown in FIG. 3, the Si target used for forming silicon oxide film 122 is replaced with the Al target. Then, the gaseous oxygen is introduced into film deposition chamber 200 through gas inlet port 201 at a flow rate of 6.5 sccm. In addition, in order to efficiently generate plasma so as to increase a film deposition speed, the gaseous argon is introduced at a flow rate of 40 sccm. Then, in order to sputter the Al target, RF power of 500 W is applied to the Al target and microwave power of 500 W necessary for generating plasma is applied, whereby aluminum oxide film 116 having an index of refraction of 1.68 with respect to light of a wavelength of 400 nm is formed at the film deposition rate of 20 nm/second. Thus, reflectance control film 121 constituted of aluminum oxide film 115, silicon oxide film 122, and aluminum oxide film 116 is formed on coating film 114.
  • Aluminum oxynitride film 118, aluminum oxide film 119, and high-reflection film 120 on light-reflecting facet of cavity 117 can also be formed with ECR sputtering, as in the case of coating film 114 and the like. Here, before forming these films, preferably, cleaning through heating and/or cleaning with plasma irradiation is also performed. It is noted here that deterioration of the light-emitting portion gives rise to a problem on the light-emitting side where optical density is great, whereas deterioration does not cause a problem on the light-reflection side in many cases because optical density is smaller on the light-reflection side than on the light-emitting side. Therefore, in the present invention, it is not necessary to provide a film such as an aluminum oxynitride film on light-reflecting facet of cavity 117. In addition, in the present embodiment, aluminum oxynitride film 118 having a thickness of 6 nm is formed on light-reflecting facet of cavity 117, however, aluminum oxynitride film 118 may have a greater thickness, for example, of 50 nm.
  • After the films described above are formed on light-emitting facet of cavity 113 and light-reflecting facet of cavity 117, heat treatment may be performed. Thus, removal of moisture contained in the films or improvement in film quality through heat treatment can be expected.
  • As described above, coating film 114, aluminum oxide film 115, silicon oxide film 122, and aluminum oxide film 116 are successively formed on light-emitting facet of cavity 113 of the sample, and aluminum oxynitride film 118, aluminum oxide film 119, and high-reflection film 120 are successively formed on light-reflecting facet of cavity 117. Thereafter, the sample is divided into chips, to thereby obtain nitride semiconductor laser devices 100 shown in FIG. 1.
  • FIG. 5 shows results of theoretical calculation of reflectance spectrum at light-emitting facet of cavity 113 of nitride semiconductor laser device 100 structured as described above. It can be seen from FIG. 5 that high reflectance of approximately 30% with respect to light of a wavelength of 405 nm can be obtained at light-emitting facet of cavity 113 of nitride semiconductor laser device 100.
  • FIG. 6 shows results of actual measurement of reflectance spectrum at light-emitting facet of cavity 113 of nitride semiconductor laser device 100 structured as described above. It can be seen from FIG. 6 that high reflectance of approximately 30% with respect to light of a wavelength of 405 nm can be obtained at light-emitting facet of cavity 113 of nitride semiconductor laser device 100, which is substantially the same as the theoretical calculation result shown in FIG. 5.
  • The theoretical calculation result of reflectance spectrum shown in FIG. 5 was obtained by theoretical calculation based on measurement of a thickness and an index of refraction with respect to light of a wavelength of 400 nm n, of each layer forming nitride semiconductor laser device 100. Here, the thickness and the index of refraction with respect to light of a wavelength of 400 nm of each layer constituting nitride semiconductor laser device 100 were found using ellipsometry. In addition, the actual reflectance spectrum shown in FIG. 6 was found based on spectroscopy of white light and measurement of reflectance with respect to light of each wavelength.
  • The COD level after aging (80° C., CW drive, optical output of 40 mW, 300 hours) of nitride semiconductor laser device 100 described above was examined, and the results are as shown in FIG. 7. As shown in FIG. 7, it was found that the COD level after aging of nitride semiconductor laser device 100 was very high around 350 to 400 mW.
  • Alternatively, a nitride semiconductor laser device according to a comparative example, having a structure the same as nitride semiconductor laser device 100 except that reflectance control film 121 as above was directly formed on light-emitting facet of cavity 113 without coating film 114, was fabricated. Then, the COD level after aging (80° C., CW drive, optical output of 40 mW, 300 hours) of the nitride semiconductor laser device according to the comparative example was examined. The results are as shown in FIG. 10. As shown in FIG. 10, it was found that the COD level after aging of the nitride semiconductor laser device according to the comparative example was approximately 200 to 250 mW, which is significantly lower than that of nitride semiconductor laser device 100 described above.
  • The reason why the COD level after aging of nitride semiconductor laser device 100 was thus higher than that of the nitride semiconductor laser device according to the comparative example may be because the number of nonradiative centers at an interface between light-emitting facet of cavity 113 and coating film 114 decreased as a result of formation of coating film 114 on light-emitting facet of cavity 113 and/or because close contact between light-emitting facet of cavity 113 and coating film 114 was attained.
  • Thereafter, dependency on the COD level of the oxygen content in coating film 114 of nitride semiconductor laser device 100 was examined. The results are as shown in FIG. 8. Here, the oxygen content in coating film 114 was varied from O atomic % to 50 atomic %, and the COD level of nitride semiconductor laser device 100 after aging for 300 hours (300 hours, 80° C., optical output of 100 mW, CW drive) was measured. Here, when the oxygen content in coating film 114 is varied, the content of aluminum (atomic %) in coating film 114 hardly varies and the content of nitrogen (atomic %) decreases in correspondence with increase in the content of oxygen (atomic %), because both of oxygen and nitrogen can basically bond to aluminum.
  • As shown in FIG. 8, it can be seen that, when the oxygen content in coating film 114 is in a range from at least 0 atomic % to at most 35 atomic %, in particular when the oxygen content in coating film 114 is in a range from at least 2 atomic % to at most 30 atomic %, the COD level tends to be very high at 300 mW or greater. Therefore, the oxygen content in coating film 114 formed on light-emitting facet of cavity 113 is preferably in a range from at least 0 atomic % to at most 35 atomic % and more preferably in a range from at least 2 atomic % to at most 30 atomic %, in which case the COD level after aging tends to improve. Naturally, when the oxygen content in coating film 114 is set to 0 atomic %, coating film 114 is formed of an aluminum nitride film, and when the oxygen content is greater than 0 atomic %, coating film 114 is formed of an aluminum oxynitride film.
  • As shown in FIG. 8, the reason why the COD level can be high when the oxygen content in coating film 114 formed on light-emitting facet of cavity 113 is in a range from at least 0 atomic % to at most 35 atomic % may be because close contact between facet of cavity 113 formed of a nitride semiconductor and coating film 114 is improved and generation of nonradiative recombination level due to oxidation of facet of cavity 113 does not affect the COD level.
  • When the oxygen content is set to 0 atomic %, the COD level is slightly lower. This may be because aluminum nitride composing coating film 114 has large internal stress and contact between facet of cavity 113 and coating film 114 becomes weaker. The present inventors, however, have found that the COD level improves when silicon nitride is contained in coating film 114 composed of aluminum nitride. This may be because silicon nitride mitigates the internal stress of aluminum nitride.
  • In addition, if the oxygen content in coating film 114 is greater than 35 atomic %, it is considered that a part of facet of cavity 113 formed of a nitride semiconductor is oxidized by oxygen contained in coating film 114 and such oxidation results in nonradiative recombination level, which has led to lower COD level.
  • FIG. 9A shows results of theoretical calculation of reflectance spectrum at light-emitting facet of cavity 113 of another exemplary nitride semiconductor laser device, that is structured similarly to nitride semiconductor laser device 100 described above except that coating film 114 formed of an aluminum nitride film having a thickness of 24 nm, a silicon oxide film having a thickness of 64 nm, an aluminum nitride film having a thickness of 24 nm, and an aluminum oxide film having a thickness of 24 nm are successively formed on light-emitting facet of cavity 113. Here, the aluminum nitride film has the index of refraction of 2.1 with respect to light of a wavelength of 400 nm, the silicon oxide film has the index of refraction of 1.43 with respect to light of a wavelength of 400 nm, and the aluminum oxide film has the index of refraction of 1.68 with respect to light of a wavelength of 400 nm.
  • FIG. 9B shows results of theoretical calculation of reflectance spectrum at light-emitting facet of cavity 113 of another exemplary nitride semiconductor laser device, that is structured similarly to nitride semiconductor laser device 100 described above except that coating film 114 formed of an aluminum nitride film having a thickness of 3 nm, an aluminum oxide film having a thickness of 117 nm, a silicon oxide film having a thickness of 71 nm, an aluminum oxide film having a thickness of 60 nm, a silicon oxide film having a thickness of 71 nm, and an aluminum oxide film having a thickness of 60 nm are successively formed on light-emitting facet of cavity 113. Here, the aluminum nitride film has the index of refraction of 2.1 with respect to light of a wavelength of 400 nm, the aluminum oxide film has the index of refraction of 1.68 with respect to light of a wavelength of 400 nm, and the silicon oxide film has the index of refraction of 1.43 with respect to light of a wavelength of 400 nm.
  • As can clearly be seen from comparison of FIGS. 5, 9A and 9B, the reflectance can be controlled by varying film structure on light-emitting facet of cavity 113.
  • It is noted that aluminum oxynitride discussed in the present invention may take any form in the present invention; aluminum oxide may be mixed in AlN, crystals of aluminum oxynitride may be present in AlN, or aluminum oxide and aluminum oxynitride may be present in AlN.
  • In the embodiment above, an example where the oxygen content in the coating film composed of aluminum oxynitride is substantially uniform in the direction of thickness has been described, however, a coating film having a multi-layer structure with the oxygen content gradually varied or different in the direction of thickness may be formed.
  • Meanwhile, in the embodiment above, preferably, coating film 114 has a thickness of at least 1 nm. If coating film 114 has a thickness less than 1 nm, it becomes difficult to control the thickness of coating film 114, and coating film 114 may not be formed on light-emitting facet of cavity 113. On the other hand, even when the thickness of coating film 114 is too large, it is assumed that the effect of the present invention is not impaired, although internal stress of coating film 114 may give rise to a problem. From the point of view of improvement in controllability of the thickness of coating film 114 and controllability of the reflectance at light-emitting facet of cavity 113, coating film 114 preferably has a thickness in a range from at least 3 nm to at most 50 nm.
  • The COD level of nitride semiconductor laser device 100 described above is significantly affected by coating film 114 on light-emitting facet of cavity 113, but not much affected by reflectance control film 121 on coating film 114. Therefore, in the present invention, reflectance control film 121 can be designed relatively freely, taking into consideration only the reflectance at light-emitting facet of cavity 113, and hence the degree of freedom in design remarkably improves.
  • In addition, in the embodiment above, if coating film 114 is formed of an aluminum oxynitride film, coating film 114 may also be formed, for example, with reactive sputtering, by providing a target composed of aluminum oxide in the film deposition chamber and introducing solely gaseous nitrogen into the film deposition chamber. If such a target composed of aluminum oxide is employed, the aluminum oxynitride film can be formed without intentionally introducing gaseous oxygen into the film deposition chamber.
  • In addition, in the embodiment above, in forming coating film 114 formed of an aluminum oxynitride film, as aluminum is highly prone to oxidation, control and reproduction of a composition of oxynitride low in oxygen content tends to be difficult when gaseous oxygen is introduced in the film deposition chamber. Here, however, by using aluminum oxide less oxidized and represented in a compositional formula AlxOy (0<x<1, 0<y<0.6, x+y=1) as a target and by introducing solely gaseous nitrogen but not gaseous oxygen into the film deposition chamber, the aluminum oxynitride film low in oxygen content can relatively easily be formed. Moreover, a similar effect is obtained also when a target composed of aluminum oxynitride low in oxygen content is employed instead of the aforementioned target composed of aluminum oxide less oxidized and represented in a compositional formula AlxOy (0<x<1, 0<y<0.6, x+y=1).
  • In addition, the oxygen content in the aluminum oxynitride film can be varied also by varying film deposition conditions such as a degree of vacuum and/or a film deposition temperature in the film deposition chamber, whereby the composition of the aluminum oxynitride film can be varied. It is noted that a smaller degree of vacuum in the film deposition chamber leads to a result that an oxide is more readily taken into the aluminum oxynitride film, while a higher film deposition temperature leads to a result that an oxide is less likely to be taken into the aluminum oxynitride film.
  • If film is deposited with sputtering using a target composed of Al (Al target) with the introduction of gaseous argon and gaseous nitrogen into the film deposition chamber after an inner wall of the film deposition chamber is oxidized or aluminum oxide is formed on the inner wall of the film deposition chamber, the inner wall of the film deposition chamber has oxygen departed because of plasma, and therefore, coating film 114 formed of the aluminum oxynitride film can be formed.
  • In the present invention, for example, a nitride semiconductor mainly composed of (at least 50 mass % of the total) AlInGaN (a compound of at least one group III element selected from the group of aluminum, indium and gallium and nitrogen representing group V elements) may be employed as the nitride semiconductor.
  • In the present invention, reflectance control film 121 is not particularly limited provided that it is formed of an oxide. Among others, however, a stack of an aluminum oxide film and a silicon oxide film is preferably used as reflectance control film 121. If reflectance control film 121 is formed of the stack of the aluminum oxide film and the silicon oxide film, fluctuation in the reflectance at light-emitting facet of cavity 113 with respect to fluctuation in the thicknesses of respective films constituting reflectance control film 121 is small, and therefore, the reflectance can be reproduced with excellent controllability. In the present invention, it is noted that the stack of the aluminum oxide film and the silicon oxide film constituting reflectance control film 121 may be formed in such a manner that at least one aluminum oxide film and at least one silicon oxide film are alternately stacked.
  • In addition, in the present invention, the reflectance at light-emitting facet of cavity 113 with respect to laser beams (laser beam of a wavelength, for example, in a range from at least 370 nm to at most 470 nm) lased from nitride semiconductor laser device 100 is preferably at least 18%, more preferably at least 30%, and further preferably at least 40%. When the reflectance at light-emitting facet of cavity 113 is 18% or greater, generally, optical density at facet of cavity 113 is increased and it is less likely that high COD level is obtained. In the present invention, however, as the coating film formed of the aluminum oxynitride film or the aluminum nitride film is formed on facet of cavity 113, it is likely that high COD level is obtained. On the other hand, when the reflectance at light-emitting facet of cavity 113 is 30% or greater, in particular 40% or greater, fluctuation in the reflectance with respect to thickness of each film constituting reflectance control film 121 can be made smaller by forming reflectance control film 121 with the stack of the aluminum oxide film and the silicon oxide film. Thus, it is likely that yield is improved.
  • The present invention is suitably used, for example, for a nitride semiconductor light-emitting device such as a nitride semiconductor laser device lasing at a wavelength in ultraviolet to green range, a nitride semiconductor laser device of a broad area type having a stripe of several tens μm in width and used for high-output applications, a nitride semiconductor light-emitting diode device lasing at a wavelength in ultraviolet to red range, or the like.
  • Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.

Claims (4)

1.-9. (canceled)
10. A nitride semiconductor light-emitting device comprising a coating film formed on a facet of a nitride semiconductor, wherein
said coating film is formed of an aluminum oxynitride film or an aluminum nitride film, and oxygen content in said coating film varies in the direction of thickness of said coating film, and said oxygen content in said coating film is in a range from at least 0 atomic % at most 35 atomic %.
11. The nitride semiconductor light-emitting device of claim 10, wherein a reflectance control film formed of an oxide is formed on said coating film.
12. A nitride semiconductor light-emitting device according to claim 10, wherein the thickness of said coating film is no less than 1 nm and no more than 50 nm.
US12/232,525 2006-04-24 2008-09-18 Nitride semiconductor light-emitting device and method of manufacturing nitride semiconductor light-emitting device Abandoned US20090026481A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US12/232,525 US20090026481A1 (en) 2006-04-24 2008-09-18 Nitride semiconductor light-emitting device and method of manufacturing nitride semiconductor light-emitting device

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP2006119500 2006-04-24
JP2006-119500 2006-04-24
JP2007077362A JP4444304B2 (en) 2006-04-24 2007-03-23 Nitride semiconductor light emitting device and method for manufacturing nitride semiconductor light emitting device
JP2007-077362 2007-03-23
US11/785,981 US8319235B2 (en) 2006-04-24 2007-04-23 Nitride semiconductor light-emitting device and method of manufacturing nitride semiconductor light-emitting device
US12/232,525 US20090026481A1 (en) 2006-04-24 2008-09-18 Nitride semiconductor light-emitting device and method of manufacturing nitride semiconductor light-emitting device

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US11/785,981 Continuation US8319235B2 (en) 2006-04-24 2007-04-23 Nitride semiconductor light-emitting device and method of manufacturing nitride semiconductor light-emitting device

Publications (1)

Publication Number Publication Date
US20090026481A1 true US20090026481A1 (en) 2009-01-29

Family

ID=38618649

Family Applications (2)

Application Number Title Priority Date Filing Date
US11/785,981 Active US8319235B2 (en) 2006-04-24 2007-04-23 Nitride semiconductor light-emitting device and method of manufacturing nitride semiconductor light-emitting device
US12/232,525 Abandoned US20090026481A1 (en) 2006-04-24 2008-09-18 Nitride semiconductor light-emitting device and method of manufacturing nitride semiconductor light-emitting device

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US11/785,981 Active US8319235B2 (en) 2006-04-24 2007-04-23 Nitride semiconductor light-emitting device and method of manufacturing nitride semiconductor light-emitting device

Country Status (3)

Country Link
US (2) US8319235B2 (en)
JP (1) JP4444304B2 (en)
CN (1) CN101794965B (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090218593A1 (en) * 2005-12-16 2009-09-03 Takeshi Kamikawa Nitride semiconductor light emitting device and method of frabicating nitride semiconductor laser device
US20110057220A1 (en) * 2009-09-09 2011-03-10 Atsunori Mochida Nitride semiconductor light-emitting device
US20120319162A1 (en) * 2010-03-01 2012-12-20 Sharp Kabushiki Kaisha Method for manufacturing nitride semiconductor device, nitride semiconductor light-emitting device, and light-emitting apparatus
US9202988B2 (en) 2012-06-29 2015-12-01 Panasonic Intellectual Property Management Co., Ltd. Nitride semiconductor light-emitting element
US9312659B2 (en) 2012-12-19 2016-04-12 Panasonic Intellectual Property Management Co., Ltd. Nitride semiconductor laser element

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4451371B2 (en) * 2004-12-20 2010-04-14 シャープ株式会社 Nitride semiconductor laser device
JP2007103814A (en) * 2005-10-07 2007-04-19 Sharp Corp Nitride semiconductor light emitting device and its manufacturing method
KR100853241B1 (en) * 2005-12-16 2008-08-20 샤프 가부시키가이샤 Nitride Semiconductor Light Emitting Device and Method of Fabricating Nitride Semiconductor Laser Device
JP5004597B2 (en) 2006-03-06 2012-08-22 シャープ株式会社 Nitride semiconductor light emitting device and method for manufacturing nitride semiconductor light emitting device
JP5430826B2 (en) 2006-03-08 2014-03-05 シャープ株式会社 Nitride semiconductor laser device
JP5193718B2 (en) 2008-07-18 2013-05-08 パナソニック株式会社 Nitride semiconductor laser device
JP2010109144A (en) * 2008-10-30 2010-05-13 Sanyo Electric Co Ltd Semiconductor laser device and method of manufacturing the same
JP2010135516A (en) * 2008-12-03 2010-06-17 Panasonic Corp Nitride semiconductor light emitting device
JP5383313B2 (en) 2009-05-20 2014-01-08 パナソニック株式会社 Nitride semiconductor light emitting device
JP5319397B2 (en) 2009-05-27 2013-10-16 シャープ株式会社 Semiconductor laser device
CN102828149A (en) * 2011-06-13 2012-12-19 鸿富锦精密工业（深圳）有限公司 Film-coating member and manufacturing method thereof
CN108631153A (en) * 2017-03-22 2018-10-09 山东华光光电子股份有限公司 A kind of total reflection light waveguide semiconductor chip of laser and preparation method thereof

Citations (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5196958A (en) * 1989-10-31 1993-03-23 U.S. Philips Corporation Optical amplifier having gain at two separated wavelengths
US5231062A (en) * 1990-08-09 1993-07-27 Minnesota Mining And Manufacturing Company Transparent aluminum oxynitride-based ceramic article
US5741724A (en) * 1996-12-27 1998-04-21 Motorola Method of growing gallium nitride on a spinel substrate
US5777792A (en) * 1993-08-25 1998-07-07 Fujitsu Limited Optical film, an antireflection film, a reflection film, a method for forming the optical film, the antireflection film or the reflection film and an optical device
US6249534B1 (en) * 1998-04-06 2001-06-19 Matsushita Electronics Corporation Nitride semiconductor laser device
US20020006726A1 (en) * 1998-01-08 2002-01-17 Shiro Yamasaki Method for manufacturing group iii nitride compound semiconductor laser diodes
US20020024981A1 (en) * 2000-06-20 2002-02-28 Tsuyoshi Tojo Semiconductor laser
US6370177B1 (en) * 1998-03-30 2002-04-09 Kabushiki Kaisha Toshiba Semiconductor laser and method of manufacturing the same
US20030015715A1 (en) * 2001-06-29 2003-01-23 Shiro Sakai Gallium nitride-based light emitting device
US20030015713A1 (en) * 2001-07-17 2003-01-23 Yoo Myung Cheol Diode having high brightness and method thereof
US20040026710A1 (en) * 2000-09-21 2004-02-12 Yuhzoh Tsuda Nitride semiconductor light emitting element and optical device containing it
US6744076B2 (en) * 2002-03-14 2004-06-01 The Circle For The Promotion Of Science And Engineering Single crystalline aluminum nitride film, method of forming the same, base substrate for group III element nitride film, light emitting device and surface acoustic wave device
US20040165635A1 (en) * 2001-05-31 2004-08-26 Yasunobu Sugimoto Semiconductor laser element
US20040190576A1 (en) * 2003-03-27 2004-09-30 Mitsubishi Denki Kabushiki Kaisha Semiconductor laser devices
US20040213314A1 (en) * 2003-04-23 2004-10-28 Mitsubishi Denki Kabushiki Kaisha Semiconductor laser device
US6812152B2 (en) * 2001-08-09 2004-11-02 Comlase Ab Method to obtain contamination free laser mirrors and passivation of these
US20040238810A1 (en) * 2001-10-26 2004-12-02 Robert Dwilinski Nitride semiconductor laser device and manufacturing method therefor
US20040245535A1 (en) * 2000-10-23 2004-12-09 General Electric Company Homoepitaxial gallium-nitride-based light emitting device and method for producing
US20050032344A1 (en) * 2002-03-08 2005-02-10 Toyoda Gosei Co., Ltd. Group III nitride compound semiconductor laser
US20050059181A1 (en) * 2003-09-01 2005-03-17 Keiji Yamane Semiconductor laser manufacturing method
US20050104162A1 (en) * 2003-11-14 2005-05-19 Xueping Xu Vicinal gallium nitride substrate for high quality homoepitaxy
US20050127383A1 (en) * 2003-12-10 2005-06-16 Takeshi Kikawa Laser diode and manufacturing method thereof
US6961359B2 (en) * 2001-04-12 2005-11-01 Sony Corporation Semiconductor laser device
US20050281304A1 (en) * 2004-03-15 2005-12-22 Atsunori Mochida Semiconductor laser device and method for fabricating the same
US20060093005A1 (en) * 2004-10-29 2006-05-04 Mitsubishi Denki Kabushiki Kaisha Semiconductor laser
US20060133442A1 (en) * 2004-12-20 2006-06-22 Masahumi Kondou Nitride semiconductor light-emitting device and method for fabrication thereof
US20060280668A1 (en) * 2001-07-06 2006-12-14 Technologies And Devices International, Inc. Method and apparatus for fabricating crack-free group III nitride semiconductor materials
US20070014323A1 (en) * 2005-07-13 2007-01-18 Kabushiki Kaisha Toshiba Semiconductor device and method for manufacturing the same
US20070138491A1 (en) * 2005-12-16 2007-06-21 Sharp Kabushiki Kaisha Nitride semiconductor light emitting device and method of fabricating nitride semiconductor laser device
US20070200493A1 (en) * 2005-10-19 2007-08-30 Epistar Corporation Light-emitting apparatus
US20070205424A1 (en) * 2006-03-06 2007-09-06 Sharp Kabushiki Kaisha Nitride semiconductor light emitting device, method of manufacturing nitride semiconductor light emitting device, and nitride semiconductor transistor device
US20070210324A1 (en) * 2006-03-08 2007-09-13 Sharp Kabushiki Kasha Nitride semiconductor light emitting device
US7564884B1 (en) * 2005-09-27 2009-07-21 Panasonic Corporation Ridge-stripe semiconductor laser

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2884603B2 (en) 1989-07-17 1999-04-19 住友電気工業株式会社 Semiconductor laser device
JP2743106B2 (en) 1990-01-12 1998-04-22 アルプス電気株式会社 Semiconductor laser
JPH09194204A (en) 1995-11-16 1997-07-29 Matsushita Electric Ind Co Ltd Production of aluminum nitride and light emitting semiconductor device
JPH09162496A (en) 1995-12-12 1997-06-20 Nippon Telegr & Teleph Corp <Ntt> Semiconductor laser and its manufacture
JP3774503B2 (en) 1996-04-17 2006-05-17 日本オプネクスト株式会社 Semiconductor laser device and manufacturing method thereof
JP4033644B2 (en) 2000-07-18 2008-01-16 日亜化学工業株式会社 Gallium nitride light emitting device
JP2002237648A (en) 2001-02-13 2002-08-23 Fuji Photo Film Co Ltd Semiconductor laser element
JP4977931B2 (en) 2001-03-06 2012-07-18 ソニー株式会社 GaN semiconductor laser manufacturing method
JP2003078199A (en) * 2001-09-03 2003-03-14 Fuji Photo Film Co Ltd Semiconductor laser device
JP2005340625A (en) 2004-05-28 2005-12-08 Nichia Chem Ind Ltd Nitride semiconductor laser device

Patent Citations (34)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5196958A (en) * 1989-10-31 1993-03-23 U.S. Philips Corporation Optical amplifier having gain at two separated wavelengths
US5231062A (en) * 1990-08-09 1993-07-27 Minnesota Mining And Manufacturing Company Transparent aluminum oxynitride-based ceramic article
US5777792A (en) * 1993-08-25 1998-07-07 Fujitsu Limited Optical film, an antireflection film, a reflection film, a method for forming the optical film, the antireflection film or the reflection film and an optical device
US5741724A (en) * 1996-12-27 1998-04-21 Motorola Method of growing gallium nitride on a spinel substrate
US20020006726A1 (en) * 1998-01-08 2002-01-17 Shiro Yamasaki Method for manufacturing group iii nitride compound semiconductor laser diodes
US6667187B2 (en) * 1998-03-30 2003-12-23 Kabushiki Kaisha Toshiba Semiconductor laser and method of manufacturing the same
US6370177B1 (en) * 1998-03-30 2002-04-09 Kabushiki Kaisha Toshiba Semiconductor laser and method of manufacturing the same
US6249534B1 (en) * 1998-04-06 2001-06-19 Matsushita Electronics Corporation Nitride semiconductor laser device
US20020024981A1 (en) * 2000-06-20 2002-02-28 Tsuyoshi Tojo Semiconductor laser
US20040026710A1 (en) * 2000-09-21 2004-02-12 Yuhzoh Tsuda Nitride semiconductor light emitting element and optical device containing it
US20040245535A1 (en) * 2000-10-23 2004-12-09 General Electric Company Homoepitaxial gallium-nitride-based light emitting device and method for producing
US6961359B2 (en) * 2001-04-12 2005-11-01 Sony Corporation Semiconductor laser device
US20040165635A1 (en) * 2001-05-31 2004-08-26 Yasunobu Sugimoto Semiconductor laser element
US20030015715A1 (en) * 2001-06-29 2003-01-23 Shiro Sakai Gallium nitride-based light emitting device
US20060280668A1 (en) * 2001-07-06 2006-12-14 Technologies And Devices International, Inc. Method and apparatus for fabricating crack-free group III nitride semiconductor materials
US20030015713A1 (en) * 2001-07-17 2003-01-23 Yoo Myung Cheol Diode having high brightness and method thereof
US6812152B2 (en) * 2001-08-09 2004-11-02 Comlase Ab Method to obtain contamination free laser mirrors and passivation of these
US20040238810A1 (en) * 2001-10-26 2004-12-02 Robert Dwilinski Nitride semiconductor laser device and manufacturing method therefor
US20050032344A1 (en) * 2002-03-08 2005-02-10 Toyoda Gosei Co., Ltd. Group III nitride compound semiconductor laser
US6744076B2 (en) * 2002-03-14 2004-06-01 The Circle For The Promotion Of Science And Engineering Single crystalline aluminum nitride film, method of forming the same, base substrate for group III element nitride film, light emitting device and surface acoustic wave device
US20040190576A1 (en) * 2003-03-27 2004-09-30 Mitsubishi Denki Kabushiki Kaisha Semiconductor laser devices
US20040213314A1 (en) * 2003-04-23 2004-10-28 Mitsubishi Denki Kabushiki Kaisha Semiconductor laser device
US20050059181A1 (en) * 2003-09-01 2005-03-17 Keiji Yamane Semiconductor laser manufacturing method
US20050104162A1 (en) * 2003-11-14 2005-05-19 Xueping Xu Vicinal gallium nitride substrate for high quality homoepitaxy
US20050127383A1 (en) * 2003-12-10 2005-06-16 Takeshi Kikawa Laser diode and manufacturing method thereof
US20050281304A1 (en) * 2004-03-15 2005-12-22 Atsunori Mochida Semiconductor laser device and method for fabricating the same
US20060093005A1 (en) * 2004-10-29 2006-05-04 Mitsubishi Denki Kabushiki Kaisha Semiconductor laser
US20060133442A1 (en) * 2004-12-20 2006-06-22 Masahumi Kondou Nitride semiconductor light-emitting device and method for fabrication thereof
US20070014323A1 (en) * 2005-07-13 2007-01-18 Kabushiki Kaisha Toshiba Semiconductor device and method for manufacturing the same
US7564884B1 (en) * 2005-09-27 2009-07-21 Panasonic Corporation Ridge-stripe semiconductor laser
US20070200493A1 (en) * 2005-10-19 2007-08-30 Epistar Corporation Light-emitting apparatus
US20070138491A1 (en) * 2005-12-16 2007-06-21 Sharp Kabushiki Kaisha Nitride semiconductor light emitting device and method of fabricating nitride semiconductor laser device
US20070205424A1 (en) * 2006-03-06 2007-09-06 Sharp Kabushiki Kaisha Nitride semiconductor light emitting device, method of manufacturing nitride semiconductor light emitting device, and nitride semiconductor transistor device
US20070210324A1 (en) * 2006-03-08 2007-09-13 Sharp Kabushiki Kasha Nitride semiconductor light emitting device

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090218593A1 (en) * 2005-12-16 2009-09-03 Takeshi Kamikawa Nitride semiconductor light emitting device and method of frabicating nitride semiconductor laser device
US20110057220A1 (en) * 2009-09-09 2011-03-10 Atsunori Mochida Nitride semiconductor light-emitting device
US20120319162A1 (en) * 2010-03-01 2012-12-20 Sharp Kabushiki Kaisha Method for manufacturing nitride semiconductor device, nitride semiconductor light-emitting device, and light-emitting apparatus
US8647904B2 (en) * 2010-03-01 2014-02-11 Sharp Kabushiki Kaisha Method for manufacturing nitride semiconductor device, nitride semiconductor light-emitting device, and light-emitting apparatus
US9202988B2 (en) 2012-06-29 2015-12-01 Panasonic Intellectual Property Management Co., Ltd. Nitride semiconductor light-emitting element
US9312659B2 (en) 2012-12-19 2016-04-12 Panasonic Intellectual Property Management Co., Ltd. Nitride semiconductor laser element

Also Published As

Publication number Publication date
CN101794965B (en) 2013-04-03
CN101794965A (en) 2010-08-04
JP2007318088A (en) 2007-12-06
US8319235B2 (en) 2012-11-27
JP4444304B2 (en) 2010-03-31
US20070246720A1 (en) 2007-10-25

Similar Documents

Publication Publication Date Title
US8319235B2 (en) Nitride semiconductor light-emitting device and method of manufacturing nitride semiconductor light-emitting device
JP5191650B2 (en) Nitride semiconductor light emitting device and method for manufacturing nitride semiconductor light emitting device
US9660413B2 (en) Nitride semiconductor light emitting device
JP5004597B2 (en) Nitride semiconductor light emitting device and method for manufacturing nitride semiconductor light emitting device
US7602829B2 (en) Semiconductor light emitting device and method of manufacturing same
JP5456928B2 (en) Nitride semiconductor light emitting device
US7759684B2 (en) Nitride semiconductor light emitting device and method for fabricating the same
US20110057220A1 (en) Nitride semiconductor light-emitting device
JP5150149B2 (en) Nitride semiconductor light emitting device and method for manufacturing nitride semiconductor light emitting device
JP4776514B2 (en) Nitride semiconductor laser device
US8541796B2 (en) Nitride semiconductor light emitting device and method of fabricating nitride semiconductor laser device
US20100133582A1 (en) Nitride semiconductor light emitting device
JP4799339B2 (en) Nitride semiconductor light emitting device
US20100118908A1 (en) Semiconductor laser device
JP5766659B2 (en) Nitride semiconductor light emitting device
JP2008263247A (en) Nitride semiconductor light emitting device, and method of manufacturing nitride semiconductor light emitting device
JP2009231696A (en) Nitride semiconductor laser element and method of manufacturing the same

Legal Events

Date Code Title Description
AS Assignment

Owner name: SHARP KABUSHIKI KAISHA, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KAMIKAWA, TAKESHI;KAWAGUCHI, YOSHINOBU;REEL/FRAME:021645/0362

Effective date: 20070419

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION