WO2005124880A1 - Iii-nitride light emitting diode and method of manufacturing it - Google Patents

Iii-nitride light emitting diode and method of manufacturing it Download PDF

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Publication number
WO2005124880A1
WO2005124880A1 PCT/KR2005/000715 KR2005000715W WO2005124880A1 WO 2005124880 A1 WO2005124880 A1 WO 2005124880A1 KR 2005000715 W KR2005000715 W KR 2005000715W WO 2005124880 A1 WO2005124880 A1 WO 2005124880A1
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Prior art keywords
type
layer
algalnn
electrode
region
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PCT/KR2005/000715
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French (fr)
Inventor
Tae Kyung Yoo
Chang Tae Kim
Keuk Kim
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Epivalley Co., Ltd.
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Publication of WO2005124880A1 publication Critical patent/WO2005124880A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/15—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components with at least one potential-jump barrier or surface barrier specially adapted for light emission
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/26—Layer connectors, e.g. plate connectors, solder or adhesive layers; Manufacturing methods related thereto
    • H01L2224/31—Structure, shape, material or disposition of the layer connectors after the connecting process
    • H01L2224/32—Structure, shape, material or disposition of the layer connectors after the connecting process of an individual layer connector
    • H01L2224/321—Disposition
    • H01L2224/32151—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/32221—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/32245—Disposition the layer connector connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805—Shape
    • H01L2224/4809—Loop shape
    • H01L2224/48091—Arched
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48135—Connecting between different semiconductor or solid-state bodies, i.e. chip-to-chip
    • H01L2224/48137—Connecting between different semiconductor or solid-state bodies, i.e. chip-to-chip the bodies being arranged next to each other, e.g. on a common substrate
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48245—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H01L2224/48247—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic connecting the wire to a bond pad of the item
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
    • H01L2224/732—Location after the connecting process
    • H01L2224/73251—Location after the connecting process on different surfaces
    • H01L2224/73265—Layer and wire connectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01046—Palladium [Pd]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01077—Iridium [Ir]
    • H—ELECTRICITY
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    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01078—Platinum [Pt]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/01—Chemical elements
    • H01L2924/01079—Gold [Au]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/11—Device type
    • H01L2924/12—Passive devices, e.g. 2 terminal devices
    • H01L2924/1203—Rectifying Diode
    • H01L2924/12032—Schottky diode
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/11—Device type
    • H01L2924/12—Passive devices, e.g. 2 terminal devices
    • H01L2924/1204—Optical Diode
    • H01L2924/12041—LED
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/02—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor bodies
    • H01L33/26—Materials of the light emitting region
    • H01L33/30—Materials of the light emitting region containing only elements of group III and group V of the periodic system
    • H01L33/32—Materials of the light emitting region containing only elements of group III and group V of the periodic system containing nitrogen

Definitions

  • the present invention relates to an AlGalnN-based light-emitting diode and a manufacturing method thereof, and more particularly, to an essential solution to reverse voltage application characteristics which are the disadvantages of the prior AlGalnN- based light-emitting diode having one p-n junction.
  • the prior light-emitting diode is as low as several tens of volts in reverse breakdown voltage (Vr) so that the device is broken due to external instantaneous reverse voltage, static electricity or the like, or potential defects occur due to unknown static electricity so as to reduce the reliability of the device.
  • Vr reverse breakdown voltage
  • the prior AlGalnN-based light-emitting diode generally comprises, on the insulating sapphire substrate 100, the buffer layer 200, the n-type AlGalnN layer 210, the AlGalnN active layer 220, the p-type AlGalnN layer 230, the transparent electrode 240, the passivation film 260, the n-type metal electrode 251 and the p-type metal electrode 250.
  • the principle of the general compound semiconductor light-emitting device is a p-n junction diode structure in which holes introduced through the p-type electrode and electrons introduced through the n-type electrode combine with each other in the active layer and emit light corresponding to the energy gap of the active layer material composition.
  • electric currents flow at forward threshold voltage (Vth) and do not substantially flow up to reverse breakdown voltage (-Vr) but rapidly flow above the breakdown voltage (-Vr).
  • This breakdown voltage (-Vr) shown in FIG. 4a varies depending on the doping concentration in the p-n junction, and the crystalline quality forming the light-emitting diode structure.
  • the breakdown voltage is generally several tens of volts (10-60V). If the doping concentration in the p-n junction is increased to maintain the operating voltage of the light-emitting diode at a low level, the breakdown voltage can be lowered to 10-30 V. In this case, a phenomenon occurs where the light-emitting diode is broken due to weakness against external static electricity, or an electrical impact is applied to the p-n junction, resulting slow or rapid deterioration in the reliability of the device. Since this static electricity phenomenon often occurs particularly when assembling the device, the application of reverse voltage results in very serious reductions in the reliability and assembly yield of the device.
  • the most common technology of technologies proposed to solve the above-mentioned problems is to connect the Zener diode 120 in parallel in a reverse direction upon the assembly of the light-emitting diode, so that the Zener diode 120 becomes forward biased to absorb an electrical impact applied to the light-emitting diode (US patent No. 5,914,501 entitled “Light Emitting Diode Assembly Having Integrated Electrostatic Discharge Protection”).
  • US patent No. 5,914,501 entitled “Light Emitting Diode Assembly Having Integrated Electrostatic Discharge Protection” Although this technology is relatively simple and easily embodied, it requires addition of a new device like the Zener diode, thus causing the problems of an increase in cost, an increase in the size of the entire device, and an increase in the complexity of the assembly process.
  • 6,547,249B2 discloses a structure for protecting the light- emitting diode from ESD (electrostatic discharge), in which the structure is manufactured by forming on the left and right sides of the insulating substrate 320, two n- type layers 22, two active layers 23, and two p-type layers 24, and electrically insulating the two regions (diodes) from each other by the ion implanted region 301, and then connecting the two regions (diodes) in parallel by the metal wiring 34 on the dielectric material 30 as shown in FIG. 12b so that the two regions have opposite polarities.
  • ESD electrostatic discharge
  • This structure is one where the same diodes are connected with each other in parallel in such a manner that they have opposite polarities, and thus, as shown in FIG. 4b, the reverse current/voltage characteristics of the diodes become essentially the same as the forward current/voltage characteristics.
  • crystal defects etch pit. threading dislocation, stacking fault, etc. caused by a large mismatch of crystal lattices between a sapphire substrate used as the insulating substrate and the gallium nitride-based semiconductor cannot be completely removed.
  • Such defects are known to be 10 -10 /cm " , and because of these defects, the light-emitting diodes will be subjected to total inspection to determine the presence or absence of the defects in the light-emitting diodes by reverse electrical characteristics (breakdown voltage or reverse leakage current). Accordingly, the above structure has a serious problem in that the presence or absence of the defects in the light-emitting diode section cannot be determined since the structure has the same reverse current/voltage characteristics as the forward current/voltage characteristics.
  • US patent Nos. 6593567B2 and 6642550B 1 disclose a method of using the flip-chip technology to embody a reverse Zener diode on the flip-chip submount. Disclosure of Invention Technical Problem
  • the present invention has been made to solve the above-described problems occurring in the prior art and it is an object of the present invention to provide a light-emitting diode having a protecting element capable of resisting a reverse electrical impact, such as ESD, as well as a manufacturing method thereof.
  • Another object of the present invention is to provide a light-emitting diode with a new structure where an insulating layer on a substrate is introduced to electrically insulate a protecting element from a light-emitting diode section, as well as a manufacturing method thereof.
  • Still another object of the present invention is to provide a light-emitting diode which has a protecting element comprising a Schottky diode so that not only it can resist a reverse electrical impact but also the pass/fail of the device can be judged, as well as a manufacturing method thereof.
  • the present invention provides a Hi-nitride light-emitting diode comprising: a first region comprising a first n-type AlGalnN layer, a first active layer formed on the first n-type AlGalnN layer, a first p- type AlGalnN layer formed on the first active layer, a first p-type electrode electrically connected with the first p-type AlGalnN layer, and a first n-type electrode electrically connected with the first n-type AlGalnN layer; a second region electrically insulated from the first region and comprising a second n-type AlGalnN layer, a second active layer formed on the second n-type AlGalnN layer, a second p-type AlGalnN layer formed on the second active layer, a p-type metal electrode formed on the second p- type AlGalnN layer and forming a Schottky diode with the second p
  • the present invention provides a method for manufacturing a Hi-nitride light-emitting diode comprising a p-type AlGalnN layer, an active layer and n-type AlGalnN layer, the method comprising the step of : ( 1 ) etching the p-type AlGalnN layer, the active layer and the n-type AlGalnN layer to divide the n-type AlGalnN layer, the active layer and the p-type AlGalnN layer into a first region and a second region; (2) bonding onto the p-type AlGalnN layer of the second region a metal electrode forming a Schottky barrier with the p-type AlGalnN layer of the second region; (3) electrically insulating the first region from the second region; and (4) connecting two diodes formed of the p-type AlGalnN layer, active layer, n-type AlGalnN layer and metal electrode of the second region to one diode
  • the present invention provides a new structure of essentially removing the p-n junction breakdown of hght-emitting diodes caused by the application of reverse voltage to the light-emitting diodes, in which the reverse voltage application will affect the reliability and yield of the light-emitting diodes.
  • the present invention can protect the light-emitting diode from breakdown caused by static electricity and large reverse voltage so as to significantly improve the reliability and yield of the device.
  • the reverse leakage current of the hght-emitting diode itself can be measured without a difference in size from the prior general AlGalnN-based ligh-emitting diode.
  • FIG. 1 is a drawing illustrating the prior art disclosed in US Pat No. 5,914,501,
  • FIG. 2 is another drawing illustrating the prior art disclosed in US Pat No. 5,914,501.
  • FIG. 3 is a drawing illustrating the structure of a prior AlGalnN-based hght- emitting diode
  • FIG. 4(4a-4b) is a drawing showiing a current-voltage characteristic curve of light emitting diode
  • FIG. 5 is a drawing illustrating the cross-sectional structure of a Hl-nitride hght- emitting diode according to the present invention
  • FIG. 6 is a top view of the Ul-nitride light-emitting diode according to the present invention.
  • FIG. 7 is a top view showing another embodiment of the Ul-nitride hght-emitting diode according to the present invention.
  • FIG. 8 is a circuit view of FIG. 7,
  • FIG. 9 is a circuit view of FIG. 6,
  • FIG. 10 is a drawing illustrating the cross- sectional structure of another example of the Ul-nitride light-emitting diode according to the present invention
  • FIG. 11 is a drawing illustrating the cross-sectional structure of still another embodiment of the Ul-nitride hght-emitting diode
  • FIG. 12(12a- 12b) is a drawing illustrating the prior art disclosed in US Pat No. 6,547,249B2. Mode for the Invention
  • FIG. 5 illustrates the cross-sectional structure of a Ul-nitride light-emitting diode according to the present invention (based on the line A-A of FIG. 6).
  • the inventive hght-emitting diode comprises: the substrate 1, the buffer layer 2 formed on the substrate 1, an insulating layer 3 formed on the buffer layer 2, the n-type AlGalnN layers 4a and 4b formed on the insulating layer 3, the active layers 5a and 5b formed on the n-type AlGalnN layers 4a and 4b, the p-type AlGalnN layers 6a and 6b formed on the active layers 5a and 5b, the transparent electrode 7 formed on the p-type AlGalnN layer 6a, the p-type electrode 8a formed on the transparent electrode 7, the n- type electrode 9a formed on the n-type AlGalnN layer 4a, the p-type metal electrode 10 formed on the p-type AlGalnN layer 6b and
  • the passivation film 11 electrically insulating the upper surface of the light-emitting diode including an interval between the n-type electrode 9a and the n-type electrode 9b, the metal wiring 12 connecting the p-type electrode 8a to the n-type electrode 9b, and the metal wiring 13 connecting the n-type electrode 9a to the p-type electrode 8b.
  • a section including the n- AlGalnN layer 4a. the active layer 5a and the p-type AlGalnN layer 6a will be referred to as a light-emitting diode section, and a section including the n- AlGalnN layer 4b, the active layer 5b and the p-type AlGalnN layer 6b will be referred to as a protecting element.
  • the light-emitting diode section acts to emits light upon the application of electric currents by recombination of electrons from the n-type AlGalnN layer 4a and holes from the p- AlGalnN layer 6a in the active layer 5a, and the protecting element act to prevent the inventive Ul-nitride light-emitting diode from being broken due to the influence of reverse high voltage applied to the light-emitting diode.
  • n- AlGalnN layer 4a and the n- AlGalnN layer 4b, the active layer 5a and the active layer 5b, and the p- AlGalnN layer 6a and the p- AlGalnN layer 6b, are grown in the form of one continuous layer in the growth process.
  • each of the p- AlGalnN layer, the active multi-layer and the n- AlGalnN layer are partially removed by photographic and etching processes up to the insulating layer 3.
  • all of the thickness of the p- AlGalnN layer and the active multi-layer and an upper portion of the thickness of n-AlGalnN are partially etched by additional photographic and etching processes to partially expose the n- AlGalnN layers 4a and 4b, in order to form the n-type electrode 9a of the light- emitting section and the n-type electrode 9b of the protecting element.
  • the p-type transparent electrode 7 is formed, and on the surface of the n- AlGalnN layer 4a partially exposed by etching, the metal electrode 9a acting also as an n-type bonding pad metal is formed.
  • the protecting element is formed of the p- type Schottky electrode 10, the bonding metal pad 8b and the n-type metal electrode 9b.
  • the Schottky junction diode protecting element is formed on the insulating substrate 1 in such a manner that it is electrically insulated from and disposed in parallel adjacent to the p-n junction diode having the same structure as the light-emitting diode. Then, the p-type electrode 8a of the hght emitting diode section and the n-type electrode of the protecting element 9b, and the n-type electrode 9a of the hght-emitting diode section and the p-type electrode 8b of the protecting device, are connected with each other by metal wires 12 and 113. respectively, so as to construct a circuit where the light-emitting diode section and the protecting element are connected with each other in such a manner to have opposite polarities (see FIG. 9).
  • the protecting element comprises a stacked structure of the n- AlGalnN layer 4b, the active layer 5b, the p-AlGalnN layer 6b, and the p-type metal electrode forming a Schottky barrier with the p-type AlGalnN layer 6b.
  • one p-n junction diode is formed between the n-AlGalnN layer 4b, the active layer 5b and the p- AlGalnN layer 6b, and another diode (i.e., a c diode) which has similar characteristics to the p-n junction diode by a Schottky barrier occurring in the contact between a semiconductor and a metal is formed between the p-type AlGalnN layer 6b and the p-type metal electrode 10.
  • the protecting element thus formed can be interpreted as a Schottky junction diode connected in series to the p-n junction diode, but not a single diode.
  • the protecting element is higher in reverse operating voltage (-Vth) than one where a single p-n junction diode is connected to a light-emitting diode in parallel in a reverse direction. Accordingly, the protecting element according to the present invention can be seen as a structure where two p-n junction diodes are connected in series to each other, and this structure makes it easy to measure the reverse leakage current of the light-emitting diode.
  • FIG. 6 is a top view of the Ul-nitride light-emitting diode according to the present invention. As shown in FIG. 6, the p-type electrode 8a of the light-emitting diode section 20 is connected to the n-type 9b of the protecting element 30 by the metal wire 12, and the n-type electrode 9a of the light-emitting diode section 20 is connected to the p-type electrode 8b of the protecting element 30 by the metal wire 13.
  • FIG. 7 is a top view showing another embodiment of the Ul-nitride hght-emitting diode according to the present invention. As shown in FIG. 7, two protecting elements 30 and 40 are connected in parallel to the hght-emitting diode section 20.
  • the protecting element 30 and the protecting element 40 are connected in series, in which the n-type electrode 9b of the protecting element 30 is connected in series to the p-type electrode 8c of the protecting element 40 by a metal wiring 14. Also, the protecting elements 30 and 40 and the hght-emitting diode section 20 are connected in parallel to each other, in which the p-type electrode 8b of the protecting element 30 and the n-type electrode 9a of the light-emitting diode section 20 are connected to each other by the metal wiring 13, and the n-type electrode 9c of the protecting element 40 and the p-type electrode 8a of the light-emitting diode section 20 are connected to each other by the metal wiring 12, so that the protecting elements and the light-emitting diode section have opposite polarities.
  • FIG. 8 is a circuit view of FIG. 7. As can be seen in FIG. 8, the light-emitting diode section 20 and the protecting elements 30 and 40 are connected in parallel to each other, and the protecting element 30 and the protecting 40 are connected in series to each other.
  • a dotted line between the protecting element 30 and the protecting element 40 in FIG. 8 indicates that the present invention may comprise at least two protecting elements. However, if the number of the protecting elements becomes too large, there will be a problem in the light-emitting area of the upper surface of the light-emitting diode is decreased.
  • FIG. 9 is a circuit view of FIG. 6.
  • the light-emitting diode section 20 when forward voltage is applied with respect to the light-emitting diode section 20, the light-emitting diode section 20 will normally operate, in which the protecting element 30 becomes reverse biased so that the element will not operate.
  • the reverse breakdown voltage (Vr) of the protecting element 30 must be sufficiently greater than the forward threshold voltage (Vth) of the light-emitting diode section 20.
  • Vth forward threshold voltage
  • the reverse leakage current of the protecting element 30 must be minimized.
  • the light-emitting diode section 20 operates at normal reverse voltage as if there is no protecting element 30.
  • the light-emitting diode section 20 When reverse voltage is applied to the hght-emitting diode 20, the light-emitting diode section 20 will resist up to reverse breakdown voltage (Vr), in which at a voltage before reaching the reverse breakdown voltage, the protecting element 30 will reach the forward operating voltage and operate just like a forward light-emitting diode.
  • Vr reverse breakdown voltage
  • the forward operating voltage of the protecting element 30 When reverse voltage is applied to the light-emitting diode section 20, the forward operating voltage of the protecting element 30 will be the sum of the operating voltage of the p-n junction diode and the operating voltage of the Schottky diode.
  • the operating voltage can be increased over the range where reverse leakage current is measured in general elements. Also, it is possible to have an operating voltage in a suitable range depending on the size of the elements and the number of the connected elements.
  • the protecting elements connected to the hght-emitting diode section 20 in a reverse direction makes it possible to measure the reverse leakage current of the light-emitting diode. Accordingly, the reverse leakage current can be measured as done in general light-emitting diodes and used as a criterion for the judgment of pass/fail.
  • FIG. 10 illustrates the cross- sectional structure of another example of the Ul-nitride light-emitting diode according to the present invention.
  • the structure shown in FIG. 10 is etched up to the substrate in photographic and etching processes, but not up to the insulating layers 3a-l, 3a-2, 3a-3, 3b-l, 3b-2 and 3b-3.
  • This structure etched up to the insulating substrate has a excellent insulating characteristic as compared to the structure inserted with the insulating layers 3-1, 3-2 and 3-3 (FIG. 7).
  • the connection of the metal wirings 12 and 13 cannot be easy due to the large step height as compared to the structure of FIG. 7, it is preferable to fill the etched portion with the insulating material 14.
  • FIG. 11 illustrates the cross-sectional structure of still another embodiment of the Ul-nitride light-emitting diode.
  • the structure of FIG. 11 has no insulating layers 3a-l, 3a-2, 3a-3. 3b-l, 3b-2 and 3b-3, and it is preferable in the structure of FIG. 11 to fill the etched portion with the insulating material 15 in order to ensure the connection of the metal wirings 12 and 13, as done in the structure of FIG. 10.
  • the insulating layer 3 on the buffer layer 2 and etching the layer 3 up to the buffer layer 2 as shown in FIG. 7, an advantage capable of avoiding an additional process of filling with the insulating material 15 can be obtained.
  • the technical idea of the present invention is to form the additional p-n junction diode using the Schottky barrier in the bonding between the semiconductor and the metal.
  • a Schottky barrier Schottky diode
  • a metal/semiconductor bond between the p-type electrode 8b and the p- AlGalnN layer 6b may be used without the p-type metal electrode 10.
  • the p-type electrode 8b and the p-type electrode 8a since the p-type electrode 8b and the p-type electrode 8a.
  • the manufacturing process of the light-emitting diode becomes simple, and a separate process of forming the p-type metal electrode 10 can be omitted.
  • the material or composition of the p-type electrodes 8a and 8b, the n-type electrodes 9a and 9b, and the p-type metal electrode forming the Schottky barrier with the p- AlGalnN layer 6b is obvious to a person skilled in the art, and is preferably selected from the group consisting of nickel, gold, silver, chrome, titanium, platinum, palladium, rhodium, iridium, aluminum, ITO (indium tin oxide), and a combination of two or more of these materials.

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Abstract

The present invention relates to an AlGalnN-based light-emitting diode and a manufacturing method of the diode comprising a first region comprising a first n-type AlGaInN layer, a first active layer formed on the first n-type AlGaInN layer, a first p-type AlGaInN layer formed on the first active layer, a first p-type electrode electrically connected with the first p-type AlGaInN layer, and a first n-type electrode electrically connected with the first n-type AlGaInN layer; a second region electrically insulated from the first region and comprising a second n-type AlGaInN layer, a second active layer formed on the second n-type AlGaInN layer, a second p-type AlGaInN layer formed on the second active layer, a p-type metal electrode formed on the second p-type AlGaInN layer and forming a Schottky diode with the second p-type AlGaInN layer, a second p-type electrode formed on the p-type metal electrode, and a second n-type electrode electrically connected with the second n-type AlGaInN layer; a first connection for connecting the first p-type electrode to the second n-type electrode; and a second connection for connecting the first n-type electrode to the second p-type electrode.

Description

Description m-NITRIDE LIGHT EMITTING DIODE AND METHOD OF MANUFACTURING IT Technical Field
[1] The present invention relates to an AlGalnN-based light-emitting diode and a manufacturing method thereof, and more particularly, to an essential solution to reverse voltage application characteristics which are the disadvantages of the prior AlGalnN- based light-emitting diode having one p-n junction. Background Art
[2] The prior light-emitting diode is as low as several tens of volts in reverse breakdown voltage (Vr) so that the device is broken due to external instantaneous reverse voltage, static electricity or the like, or potential defects occur due to unknown static electricity so as to reduce the reliability of the device.
[3] As shown in FIG. 3, the prior AlGalnN-based light-emitting diode generally comprises, on the insulating sapphire substrate 100, the buffer layer 200, the n-type AlGalnN layer 210, the AlGalnN active layer 220, the p-type AlGalnN layer 230, the transparent electrode 240, the passivation film 260, the n-type metal electrode 251 and the p-type metal electrode 250.
[4] As can be seen in this structure, the principle of the general compound semiconductor light-emitting device is a p-n junction diode structure in which holes introduced through the p-type electrode and electrons introduced through the n-type electrode combine with each other in the active layer and emit light corresponding to the energy gap of the active layer material composition. In the general electrical characteristics of the light-emitting diode, electric currents flow at forward threshold voltage (Vth) and do not substantially flow up to reverse breakdown voltage (-Vr) but rapidly flow above the breakdown voltage (-Vr). This breakdown voltage (-Vr) shown in FIG. 4a varies depending on the doping concentration in the p-n junction, and the crystalline quality forming the light-emitting diode structure. For the AlGalnN-based light-emitting diode, the breakdown voltage is generally several tens of volts (10-60V). If the doping concentration in the p-n junction is increased to maintain the operating voltage of the light-emitting diode at a low level, the breakdown voltage can be lowered to 10-30 V. In this case, a phenomenon occurs where the light-emitting diode is broken due to weakness against external static electricity, or an electrical impact is applied to the p-n junction, resulting slow or rapid deterioration in the reliability of the device. Since this static electricity phenomenon often occurs particularly when assembling the device, the application of reverse voltage results in very serious reductions in the reliability and assembly yield of the device.
[5] As shown in FIG. 1, the most common technology of technologies proposed to solve the above-mentioned problems is to connect the Zener diode 120 in parallel in a reverse direction upon the assembly of the light-emitting diode, so that the Zener diode 120 becomes forward biased to absorb an electrical impact applied to the light-emitting diode (US patent No. 5,914,501 entitled "Light Emitting Diode Assembly Having Integrated Electrostatic Discharge Protection"). Although this technology is relatively simple and easily embodied, it requires addition of a new device like the Zener diode, thus causing the problems of an increase in cost, an increase in the size of the entire device, and an increase in the complexity of the assembly process.
[6] The technology to overcome these problems is to form another diode on a single layer of the light-emitting diode and to connect the second diode in the reverse direction to the light-emitting diode (US patent No. 6,547,249B2 entitled "Monolithic Series/Parallel LED Arrays Formed On Highly Resistive Substrates"). As shown in FIG. 12a, US patent No. 6,547,249B2 discloses a structure for protecting the light- emitting diode from ESD (electrostatic discharge), in which the structure is manufactured by forming on the left and right sides of the insulating substrate 320, two n- type layers 22, two active layers 23, and two p-type layers 24, and electrically insulating the two regions (diodes) from each other by the ion implanted region 301, and then connecting the two regions (diodes) in parallel by the metal wiring 34 on the dielectric material 30 as shown in FIG. 12b so that the two regions have opposite polarities.
[7] This structure is one where the same diodes are connected with each other in parallel in such a manner that they have opposite polarities, and thus, as shown in FIG. 4b, the reverse current/voltage characteristics of the diodes become essentially the same as the forward current/voltage characteristics. Currently in case of a gallium nitride-based semiconductor whose crystal grew on an insulating substrate, crystal defects (etch pit. threading dislocation, stacking fault, etc.) caused by a large mismatch of crystal lattices between a sapphire substrate used as the insulating substrate and the gallium nitride-based semiconductor cannot be completely removed. Such defects are known to be 10 -10 /cm", and because of these defects, the light-emitting diodes will be subjected to total inspection to determine the presence or absence of the defects in the light-emitting diodes by reverse electrical characteristics (breakdown voltage or reverse leakage current). Accordingly, the above structure has a serious problem in that the presence or absence of the defects in the light-emitting diode section cannot be determined since the structure has the same reverse current/voltage characteristics as the forward current/voltage characteristics.
[8] In addition, US patent Nos. 6593567B2 and 6642550B 1 disclose a method of using the flip-chip technology to embody a reverse Zener diode on the flip-chip submount. Disclosure of Invention Technical Problem
[9] Accordingly, the present invention has been made to solve the above-described problems occurring in the prior art and it is an object of the present invention to provide a light-emitting diode having a protecting element capable of resisting a reverse electrical impact, such as ESD, as well as a manufacturing method thereof.
[10] Another object of the present invention is to provide a light-emitting diode with a new structure where an insulating layer on a substrate is introduced to electrically insulate a protecting element from a light-emitting diode section, as well as a manufacturing method thereof.
[11] Still another object of the present invention is to provide a light-emitting diode which has a protecting element comprising a Schottky diode so that not only it can resist a reverse electrical impact but also the pass/fail of the device can be judged, as well as a manufacturing method thereof. Technical Solution
[12] To achieve the above objects, in one aspect, the present invention provides a Hi-nitride light-emitting diode comprising: a first region comprising a first n-type AlGalnN layer, a first active layer formed on the first n-type AlGalnN layer, a first p- type AlGalnN layer formed on the first active layer, a first p-type electrode electrically connected with the first p-type AlGalnN layer, and a first n-type electrode electrically connected with the first n-type AlGalnN layer; a second region electrically insulated from the first region and comprising a second n-type AlGalnN layer, a second active layer formed on the second n-type AlGalnN layer, a second p-type AlGalnN layer formed on the second active layer, a p-type metal electrode formed on the second p- type AlGalnN layer and forming a Schottky diode with the second p-type AlGalnN layer, a second p-type electrode formed on the p-type metal electrode, and a second n- type electrode electrically connected with the second n-type AlGalnN layer; a first connection for connecting the first p-type electrode to the second n-type electrode; and a second connection for connecting the first n-type electrode to the second p-type electrode. In this regard, the AlGalnN layer means a composition where the sum of x+y+z in Al(x)Ga(y)ln(z)N satisfies 1. For example, GaN corresponds to the composition.
[13] In another aspect, the present invention provides a method for manufacturing a Hi-nitride light-emitting diode comprising a p-type AlGalnN layer, an active layer and n-type AlGalnN layer, the method comprising the step of : ( 1 ) etching the p-type AlGalnN layer, the active layer and the n-type AlGalnN layer to divide the n-type AlGalnN layer, the active layer and the p-type AlGalnN layer into a first region and a second region; (2) bonding onto the p-type AlGalnN layer of the second region a metal electrode forming a Schottky barrier with the p-type AlGalnN layer of the second region; (3) electrically insulating the first region from the second region; and (4) connecting two diodes formed of the p-type AlGalnN layer, active layer, n-type AlGalnN layer and metal electrode of the second region to one diode formed of the p- type AlGalnN layer, active layer and n-type AlGalnN layer of the first region in parallel in such as a manner that the diodes have opposite polarities (p-n). Advantageous Effects
[14] The present invention provides a new structure of essentially removing the p-n junction breakdown of hght-emitting diodes caused by the application of reverse voltage to the light-emitting diodes, in which the reverse voltage application will affect the reliability and yield of the light-emitting diodes. Thus, the present invention can protect the light-emitting diode from breakdown caused by static electricity and large reverse voltage so as to significantly improve the reliability and yield of the device. Moreover, even in an environment where reverse voltage can exceed the breakdown voltage of the light-emitting diode, the light-emitting diode can be protected. In addition, the reverse leakage current of the hght-emitting diode itself can be measured without a difference in size from the prior general AlGalnN-based ligh-emitting diode. Brief Description of the Drawings
[15] FIG. 1 is a drawing illustrating the prior art disclosed in US Pat No. 5,914,501,
[16] FIG. 2 is another drawing illustrating the prior art disclosed in US Pat No. 5,914,501.
[17] FIG. 3 is a drawing illustrating the structure of a prior AlGalnN-based hght- emitting diode,
[18] FIG. 4(4a-4b) is a drawing showiing a current-voltage characteristic curve of light emitting diode,
[19] FIG. 5 is a drawing illustrating the cross-sectional structure of a Hl-nitride hght- emitting diode according to the present invention,
[20] FIG. 6 is a top view of the Ul-nitride light-emitting diode according to the present invention,
[21] FIG. 7 is a top view showing another embodiment of the Ul-nitride hght-emitting diode according to the present invention,
[22] FIG. 8 is a circuit view of FIG. 7,
[23] FIG. 9 is a circuit view of FIG. 6,
[24] FIG. 10 is a drawing illustrating the cross- sectional structure of another example of the Ul-nitride light-emitting diode according to the present invention, [25] FIG. 11 is a drawing illustrating the cross-sectional structure of still another embodiment of the Ul-nitride hght-emitting diode,
[26] FIG. 12(12a- 12b) is a drawing illustrating the prior art disclosed in US Pat No. 6,547,249B2. Mode for the Invention
[27] Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.
[28] FIG. 5 illustrates the cross-sectional structure of a Ul-nitride light-emitting diode according to the present invention (based on the line A-A of FIG. 6). As shown in FIG. 5, the inventive hght-emitting diode comprises: the substrate 1, the buffer layer 2 formed on the substrate 1, an insulating layer 3 formed on the buffer layer 2, the n-type AlGalnN layers 4a and 4b formed on the insulating layer 3, the active layers 5a and 5b formed on the n-type AlGalnN layers 4a and 4b, the p-type AlGalnN layers 6a and 6b formed on the active layers 5a and 5b, the transparent electrode 7 formed on the p-type AlGalnN layer 6a, the p-type electrode 8a formed on the transparent electrode 7, the n- type electrode 9a formed on the n-type AlGalnN layer 4a, the p-type metal electrode 10 formed on the p-type AlGalnN layer 6b and forming a Schottky diode with the p- type AlGalnN layer 6b. the p-type electrode 8b formed on the p-type metal electrode 10, the n-type electrode 9b formed on the n-type AlGalnN layer 4b, the passivation film 11 electrically insulating the upper surface of the light-emitting diode including an interval between the n-type electrode 9a and the n-type electrode 9b, the metal wiring 12 connecting the p-type electrode 8a to the n-type electrode 9b, and the metal wiring 13 connecting the n-type electrode 9a to the p-type electrode 8b.
[29] Hereinafter, a section including the n- AlGalnN layer 4a. the active layer 5a and the p-type AlGalnN layer 6a will be referred to as a light-emitting diode section, and a section including the n- AlGalnN layer 4b, the active layer 5b and the p-type AlGalnN layer 6b will be referred to as a protecting element. The light-emitting diode section acts to emits light upon the application of electric currents by recombination of electrons from the n-type AlGalnN layer 4a and holes from the p- AlGalnN layer 6a in the active layer 5a, and the protecting element act to prevent the inventive Ul-nitride light-emitting diode from being broken due to the influence of reverse high voltage applied to the light-emitting diode.
[30] Preferably, the buffer layer 2 is grown on the insulating substrate 1, and the undoped u-GaN layer 3-1, p-GaN layer 3-2 and undoped u-GaN layer 3-3 for the electrical insulation between the devices are sequentially grown so as to form the insulating layer 3. Then, after growing the n- AlGalnN layers 4a and 4b, The active multi-layers 5a and 5b of Al(x)Ga(y)ln(z)N/Al(xl)Ga(yl)In(zl)N are grown on which the p- AlGalnN layers 6a and 6b are grown. In this regard, the compositions of the active layers satisfy x+y+z=l and xl+yl+zl=l.
[31] The n- AlGalnN layer 4a and the n- AlGalnN layer 4b, the active layer 5a and the active layer 5b, and the p- AlGalnN layer 6a and the p- AlGalnN layer 6b, are grown in the form of one continuous layer in the growth process. However, in order to provide electrical insulation between the light-emitting diode section and the protecting element after the crystal growth, each of the p- AlGalnN layer, the active multi-layer and the n- AlGalnN layer are partially removed by photographic and etching processes up to the insulating layer 3. After the hght-emitting section and the protecting element are electrically isolated from each other as such, all of the thickness of the p- AlGalnN layer and the active multi-layer and an upper portion of the thickness of n-AlGalnN are partially etched by additional photographic and etching processes to partially expose the n- AlGalnN layers 4a and 4b, in order to form the n-type electrode 9a of the light- emitting section and the n-type electrode 9b of the protecting element. Then, on the p- AlGalnN layer 6a, the p-type transparent electrode 7 is formed, and on the surface of the n- AlGalnN layer 4a partially exposed by etching, the metal electrode 9a acting also as an n-type bonding pad metal is formed. The protecting element is formed of the p- type Schottky electrode 10, the bonding metal pad 8b and the n-type metal electrode 9b.
[32] By doing this, the Schottky junction diode protecting element is formed on the insulating substrate 1 in such a manner that it is electrically insulated from and disposed in parallel adjacent to the p-n junction diode having the same structure as the light-emitting diode. Then, the p-type electrode 8a of the hght emitting diode section and the n-type electrode of the protecting element 9b, and the n-type electrode 9a of the hght-emitting diode section and the p-type electrode 8b of the protecting device, are connected with each other by metal wires 12 and 113. respectively, so as to construct a circuit where the light-emitting diode section and the protecting element are connected with each other in such a manner to have opposite polarities (see FIG. 9).
[33] Hereinafter, the principle of the protecting element according to the present invention will be described.
[34] The protecting element comprises a stacked structure of the n- AlGalnN layer 4b, the active layer 5b, the p-AlGalnN layer 6b, and the p-type metal electrode forming a Schottky barrier with the p-type AlGalnN layer 6b. In the protecting element, one p-n junction diode is formed between the n-AlGalnN layer 4b, the active layer 5b and the p- AlGalnN layer 6b, and another diode (i.e., a c diode) which has similar characteristics to the p-n junction diode by a Schottky barrier occurring in the contact between a semiconductor and a metal is formed between the p-type AlGalnN layer 6b and the p-type metal electrode 10. [35] The protecting element thus formed can be interpreted as a Schottky junction diode connected in series to the p-n junction diode, but not a single diode. Thus, the protecting element is higher in reverse operating voltage (-Vth) than one where a single p-n junction diode is connected to a light-emitting diode in parallel in a reverse direction. Accordingly, the protecting element according to the present invention can be seen as a structure where two p-n junction diodes are connected in series to each other, and this structure makes it easy to measure the reverse leakage current of the light-emitting diode.
[36] FIG. 6 is a top view of the Ul-nitride light-emitting diode according to the present invention. As shown in FIG. 6, the p-type electrode 8a of the light-emitting diode section 20 is connected to the n-type 9b of the protecting element 30 by the metal wire 12, and the n-type electrode 9a of the light-emitting diode section 20 is connected to the p-type electrode 8b of the protecting element 30 by the metal wire 13.
[37] FIG. 7 is a top view showing another embodiment of the Ul-nitride hght-emitting diode according to the present invention. As shown in FIG. 7, two protecting elements 30 and 40 are connected in parallel to the hght-emitting diode section 20.
[38] The protecting element 30 and the protecting element 40 are connected in series, in which the n-type electrode 9b of the protecting element 30 is connected in series to the p-type electrode 8c of the protecting element 40 by a metal wiring 14. Also, the protecting elements 30 and 40 and the hght-emitting diode section 20 are connected in parallel to each other, in which the p-type electrode 8b of the protecting element 30 and the n-type electrode 9a of the light-emitting diode section 20 are connected to each other by the metal wiring 13, and the n-type electrode 9c of the protecting element 40 and the p-type electrode 8a of the light-emitting diode section 20 are connected to each other by the metal wiring 12, so that the protecting elements and the light-emitting diode section have opposite polarities.
[39] FIG. 8 is a circuit view of FIG. 7. As can be seen in FIG. 8. the light-emitting diode section 20 and the protecting elements 30 and 40 are connected in parallel to each other, and the protecting element 30 and the protecting 40 are connected in series to each other.
[40] A dotted line between the protecting element 30 and the protecting element 40 in FIG. 8 indicates that the present invention may comprise at least two protecting elements. However, if the number of the protecting elements becomes too large, there will be a problem in the light-emitting area of the upper surface of the light-emitting diode is decreased.
[41] FIG. 9 is a circuit view of FIG. 6. As shown in FIG. 9. when forward voltage is applied with respect to the light-emitting diode section 20, the light-emitting diode section 20 will normally operate, in which the protecting element 30 becomes reverse biased so that the element will not operate. In this case, the reverse breakdown voltage (Vr) of the protecting element 30 must be sufficiently greater than the forward threshold voltage (Vth) of the light-emitting diode section 20. Also, the reverse leakage current of the protecting element 30 must be minimized. In this case, the light-emitting diode section 20 operates at normal reverse voltage as if there is no protecting element 30. When reverse voltage is applied to the hght-emitting diode 20, the light-emitting diode section 20 will resist up to reverse breakdown voltage (Vr), in which at a voltage before reaching the reverse breakdown voltage, the protecting element 30 will reach the forward operating voltage and operate just like a forward light-emitting diode. When reverse voltage is applied to the light-emitting diode section 20, the forward operating voltage of the protecting element 30 will be the sum of the operating voltage of the p-n junction diode and the operating voltage of the Schottky diode.
[42] If the area of the protecting element 30 is sufficiently large or at least two protecting elements are connected in series to each other, the operating voltage can be increased over the range where reverse leakage current is measured in general elements. Also, it is possible to have an operating voltage in a suitable range depending on the size of the elements and the number of the connected elements. The protecting elements connected to the hght-emitting diode section 20 in a reverse direction makes it possible to measure the reverse leakage current of the light-emitting diode. Accordingly, the reverse leakage current can be measured as done in general light-emitting diodes and used as a criterion for the judgment of pass/fail.
[43] FIG. 10 illustrates the cross- sectional structure of another example of the Ul-nitride light-emitting diode according to the present invention. Unlike the case of FIG. 5, the structure shown in FIG. 10 is etched up to the substrate in photographic and etching processes, but not up to the insulating layers 3a-l, 3a-2, 3a-3, 3b-l, 3b-2 and 3b-3. This structure etched up to the insulating substrate has a excellent insulating characteristic as compared to the structure inserted with the insulating layers 3-1, 3-2 and 3-3 (FIG. 7). However, since the connection of the metal wirings 12 and 13 cannot be easy due to the large step height as compared to the structure of FIG. 7, it is preferable to fill the etched portion with the insulating material 14.
[44] FIG. 11 illustrates the cross-sectional structure of still another embodiment of the Ul-nitride light-emitting diode. Unlike the structure of FIG. 10, the structure of FIG. 11 has no insulating layers 3a-l, 3a-2, 3a-3. 3b-l, 3b-2 and 3b-3, and it is preferable in the structure of FIG. 11 to fill the etched portion with the insulating material 15 in order to ensure the connection of the metal wirings 12 and 13, as done in the structure of FIG. 10. Thus, by forming the insulating layer 3 on the buffer layer 2 and etching the layer 3 up to the buffer layer 2 as shown in FIG. 7, an advantage capable of avoiding an additional process of filling with the insulating material 15 can be obtained. [45] Meanwhile, the technical idea of the present invention is to form the additional p-n junction diode using the Schottky barrier in the bonding between the semiconductor and the metal. In the present invention, a Schottky barrier (Schottky diode) with a metal/semiconductor bond between the p-type electrode 8b and the p- AlGalnN layer 6b may be used without the p-type metal electrode 10. In this case, since the p-type electrode 8b and the p-type electrode 8a. and the n-type electrode 9a and the n-type electrode 9b, may be made of the same materials, there are advantages in that the manufacturing process of the light-emitting diode becomes simple, and a separate process of forming the p-type metal electrode 10 can be omitted.
[46] The material or composition of the p-type electrodes 8a and 8b, the n-type electrodes 9a and 9b, and the p-type metal electrode forming the Schottky barrier with the p- AlGalnN layer 6b, is obvious to a person skilled in the art, and is preferably selected from the group consisting of nickel, gold, silver, chrome, titanium, platinum, palladium, rhodium, iridium, aluminum, ITO (indium tin oxide), and a combination of two or more of these materials.

Claims

Claims
[1] A πi-nitride light emitting diode comprising: a substrate 1 ; a buffer layer 2 formed on the substrate 1 ; an insulating layer 3 formed on the buffer layer 2; a first n-type AlGalnN layer 4a formed on the insulating layer 3; a first active layer 5a formed on the first n-type AlGalnN layer 4a; a first p-type AlGalnN layer 6a formed on the first active layer 5a; a transparent electrode 7 formed on the p-type AlGalnN layer 6a, a first p-type electrode 8a formed on the transparent electrode 7, a first n-type electrode 9a formed on the first n-type AlGalnN layer 4a; a second n-type AlGalnN layer 4b formed on the insulating layer 3; a second active layer 5b formed on the second n-type AlGalnN layer 4b; a second p-type AlGalnN layer 6b formed on the first active layer 5b; a p-type metal electrode 10 formed on the second p-type AlGalnN layer 6b and forming a Schottky diode with the second p-type AlGalnN layer 6b; a second p-type electrode 8b formed on the p-type metal electrode 10; a second n-type electrode 9b formed on the second n-type AlGalnN layer 4b; a passivation film 11 electrically insulating an interval between the first n-type electrode 9a and the second n-type electrode 9b; a first metal wiring 12 connecting the first p-type electrode 8a to the second n- type electrode 9b; and, a second metal wiring 13 connecting the first n-type electrode 9a to the second p- type electrode 8b.
[2] The Ul-nitride light emitting diode of claim 1 , wherein the insulating layer 3 comprises an undoped u-GaN layer 3-1 formed on the buffer layer 2, a p-GaN layer 3-2 formed on the undoped u-GaN layer 3-1, and an undoped u-GaN layer 3-3 formed on the p-GaN layer 3-2.
[3] A Ill-nitride light emitting diode comprising: an insulating substrate 1 ; a first buffer layer 2a formed on the insulating substrate 1 ; a first n-type AlGalnN layer 4a formed on the first buffer layer 2a; a first active layer 5a formed on the first n-type AlGalnN layer 4a; a first p-type AlGalnN layer 6a formed on the first active layer 5a; a transparent electrode 7 formed on the p-type AlGalnN layer 6a, a first p-type electrode 8a formed on the transparent electrode 7, a first n-type electrode 9a formed on the first n-type AlGalnN layer 4a; the second buffer layer 2b formed on the insulating substrate 1 ; a second n-type AlGalnN layer 4b formed on the second buffer layer 2b; a second active layer 5b formed on the second n-type AlGalnN layer 4b; a second p-type AlGalnN layer 6b formed on the first active layer 5b; a p-type metal electrode 10 formed on the second p-type AlGalnN layer 6b and forming a Schottky diode with the second p-type AlGalnN layer 6b; a second p-type electrode 8b formed on the p-type metal electrode 10; a second n-type electrode 9b formed on the second n-type AlGalnN layer 4b; a passivation film 11 electrically insulating an interval between the first n-type electrode 9a and the second n-type electrode 9b; a first metal wiring 12 connecting the first p-type electrode 8a to the second n- type electrode 9b; and, a second metal wiring 13 connecting the first n-type electrode 9a to the second p- type electrode 8b.
[4] The Ul-nitride light emitting diode of claim 3, wherein the insulating layer 3a is formed between the first buffer layer 2a and the first n-type AlGalnN layer 4a, and the insulating layer 3b is formed between the second buffer layer 2b and the second n-type AlGalnN layer 4b.
[5] The Ul-nitride light emitting diode of claim 4, wherein the insulating layer 3a comprises an undoped u-GaN layer 3a- 1 formed on the buffer layer 2a, a p-GaN layer 3a-2 formed on the undoped u-GaN layer 3a- 1, and an undoped u-GaN layer 3a-3 formed on the p-GaN layer 3a-2, and wherein the insulating layer 3b comprises an undoped u-GaN layer 3b- 1 formed on the buffer layer 2b, a p-GaN layer 3b-2 formed on the undoped u-GaN layer 3b- 1, and an undoped u-GaN layer 3b-3 formed on the p-GaN layer 3b-2.
[6] A Ill-nitride light-emitting diode comprising: a first region comprising a first n-type AlGalnN layer, a first active layer formed on the first n-type AlGalnN layer, a first p-type AlGalnN layer formed on the first active layer, a first p-type electrode electrically connected with the first p- type AlGalnN layer, and a first n-type electrode electrically connected with the first n-type AlGalnN layer; a second region electrically insulated from the first region and comprising a second n-type AlGalnN layer, a second active layer formed on the second n-type AlGalnN layer, a second p-type AlGalnN layer formed on the second active layer, a p-type metal electrode formed on the second p-type AlGalnN layer and forming a Schottky diode with the second p-type AlGalnN layer, a second p-type electrode formed on the p-type metal electrode, and a second n-type electrode electrically connected with the second n-type AlGalnN layer; a first connection for connecting the first p-type electrode to the second n-type electrode; and a second connection for connecting the first n-type electrode to the second p-type electrode.
[7] A πi-nitride light-emitting diode comprising: a first region comprising a first n-type AlGalnN layer, a first active layer formed on the first n-type AlGalnN layer, a first p-type AlGalnN layer formed on the first active layer, a first p-type electrode electrically connected with the first p- type AlGalnN layer, and a first n-type electrode electrically connected with the first n-type AlGalnN layer; a second region electrically insulated from the first region and comprising a second n-type AlGalnN layer, a second active layer formed on the second n-type AlGalnN layer, a second p-type AlGalnN layer formed on the second active layer, a first p-type metal electrode formed on the second p-type AlGalnN layer and forming a Schottky diode with the second p-type AlGalnN layer, a second p- type electrode formed on the first p-type metal electrode, and a second n-type electrode electrically connected with the second n-type AlGalnN layer; a third region electrically insulated from the first region and the second region, and comprising a third n-type AlGalnN layer, a third active layer formed on the third n-type AlGalnN layer, a third p-type AlGalnN layer formed on the third active layer, a second p-type metal electrode formed on the third p-type AlGalnN layer and forming a Schottky diode with the third p-type AlGalnN layer, a third p-type electrode formed on the second p-type metal electrode, and a third n-type electrode electrically connected with the third n-type AlGalnN layer; a first connection for connecting the first p-type electrode to the third n-type electrode; a second connection for connecting the first n-type electrode to the second p-type electrode; and. a third connection for connecting the second n-type electrode to the third p-type electrode.
[8] The Ul-nitride light emitting diode of claim 7, further comprising n (n>l) regions having the same structure as the third region and electrically insulated from other regions, wherein the second region, the third region and the n regions are serially connected, and wherein the serially connected second region, the third region and the n regions are connected to the first regiono in parallel.
[9] A πi-nitride light-emitting diode comprising: a first region comprising a first n-type AlGalnN layer, a first active layer formed on the first n-type AlGalnN layer, a first p-type AlGalnN layer formed on the first active layer, a first p-type electrode electrically connected with the first p- type AlGalnN layer, and a first n-type electrode electrically connected with the first n-type AlGalnN layer; a second region electrically insulated from the first region and comprising a second n-type AlGalnN layer, a second active layer formed on the second n-type AlGalnN layer, a second p-type AlGalnN layer formed on the second active layer, a metal electrode formed on the second p-type AlGalnN layer and forming a Schottky diode with the second p-type AlGalnN layer, and a second n-type electrode electrically connected with the second n-type AlGalnN layer; a first connection for connecting the first p-type electrode to the second n-type electrode; and a second connection for connecting the first n-type electrode to the metal electrode forming the Schottky diode. [10] A method for manufacturing a Ul-nitride light-emitting diode comprising a p- type AlGalnN layer, an active layer and n-type AlGalnN layer, the method comprising the step of: etching the p-type AlGalnN layer, the active layer and the n-type AlGalnN layer to divide the n-type AlGalnN layer, the active layer and the p-type AlGalnN layer into a first region and a second region; bonding onto the p-type AlGalnN layer of the second region a metal electrode forming a Schottky barrier with the p-type AlGalnN layer of the second region; electrically insulating the first region from the second region; and connecting two diodes formed of the p-type AlGalnN layer, active layer, n-type AlGalnN layer and metal electrode of the second region to one diode formed of the p-type AlGalnN layer, active layer and n-type AlGalnN layer of the first region in parallel in such as a manner that the diodes have opposite polarities (p-n).
PCT/KR2005/000715 2004-03-13 2005-03-14 Iii-nitride light emitting diode and method of manufacturing it WO2005124880A1 (en)

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