US20050227438A1 - Semiconductor device and method of manufacturing same - Google Patents

Semiconductor device and method of manufacturing same Download PDF

Info

Publication number
US20050227438A1
US20050227438A1 US11/140,756 US14075605A US2005227438A1 US 20050227438 A1 US20050227438 A1 US 20050227438A1 US 14075605 A US14075605 A US 14075605A US 2005227438 A1 US2005227438 A1 US 2005227438A1
Authority
US
United States
Prior art keywords
semiconductor
electrode
substrate
semiconductor substrate
resistance
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
US11/140,756
Inventor
Yoshifumi Okabe
Masami Yamaoka
Akira Kuroyanagi
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.)
Denso Corp
Original Assignee
Denso Corp
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 Denso Corp filed Critical Denso Corp
Priority to US11/140,756 priority Critical patent/US20050227438A1/en
Publication of US20050227438A1 publication Critical patent/US20050227438A1/en
Abandoned legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
    • H01L29/76—Unipolar devices, e.g. field effect transistors
    • H01L29/772—Field effect transistors
    • H01L29/78—Field effect transistors with field effect produced by an insulated gate
    • H01L29/7801—DMOS transistors, i.e. MISFETs with a channel accommodating body or base region adjoining a drain drift region
    • H01L29/7802—Vertical DMOS transistors, i.e. VDMOS transistors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268
    • H01L21/283—Deposition of conductive or insulating materials for electrodes conducting electric current
    • H01L21/285—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation
    • H01L21/28506—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers
    • H01L21/28512—Deposition of conductive or insulating materials for electrodes conducting electric current from a gas or vapour, e.g. condensation of conductive layers on semiconductor bodies comprising elements of Group IV of the Periodic System
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
    • H01L21/304—Mechanical treatment, e.g. grinding, polishing, cutting
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
    • H01L29/06—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions
    • H01L29/0657—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions characterised by the shape of the body
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
    • H01L29/30—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by physical imperfections; having polished or roughened surface
    • H01L29/34—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by physical imperfections; having polished or roughened surface the imperfections being on the surface
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/40—Electrodes ; Multistep manufacturing processes therefor
    • H01L29/41—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions
    • H01L29/417—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions carrying the current to be rectified, amplified or switched
    • H01L29/41725—Source or drain electrodes for field effect devices
    • H01L29/41741—Source or drain electrodes for field effect devices for vertical or pseudo-vertical devices
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007—Multistep manufacturing processes
    • H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66409—Unipolar field-effect transistors
    • H01L29/66477—Unipolar field-effect transistors with an insulated gate, i.e. MISFET
    • H01L29/66674—DMOS transistors, i.e. MISFETs with a channel accommodating body or base region adjoining a drain drift region
    • H01L29/66712—Vertical DMOS transistors, i.e. VDMOS transistors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
    • H01L29/12—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
    • H01L29/16—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only elements of Group IV of the Periodic System
    • H01L29/167—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only elements of Group IV of the Periodic System further characterised by the doping material
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/40—Electrodes ; Multistep manufacturing processes therefor
    • H01L29/43—Electrodes ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
    • H01L29/45—Ohmic electrodes
    • H01L29/456—Ohmic electrodes on silicon
    • 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
    • H01L2924/0001—Technical content checked by a classifier
    • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
    • 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
    • H01L2924/1015—Shape
    • H01L2924/10155—Shape being other than a cuboid
    • H01L2924/10158—Shape being other than a cuboid at the passive surface
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S148/00—Metal treatment
    • Y10S148/135—Removal of substrate
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S438/00—Semiconductor device manufacturing: process
    • Y10S438/928—Front and rear surface processing
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S438/00—Semiconductor device manufacturing: process
    • Y10S438/938—Lattice strain control or utilization
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S438/00—Semiconductor device manufacturing: process
    • Y10S438/964—Roughened surface
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S438/00—Semiconductor device manufacturing: process
    • Y10S438/977—Thinning or removal of substrate

Definitions

  • This invention relates to a semiconductor device which has a low ON-resistance, and further, to a method of manufacturing such a semiconductor device.
  • Japanese Unexamined Patent Publication 1-169970 discloses a method which an N-type impurity layer is formed in a back surface of a drain substrate so as to reduce a contact resistance between the drain substrate and a drain electrode.
  • Japanese Examined Patent Publication 58-45814 discloses a method of manufacturing the semiconductor device which has a good ohmic contact between the drain substrate and the drain electrode.
  • the device has a multilayer metal electrode on a back surface of a drain substrate.
  • the multilayer metal electrode consists of layers having a gold layer as a main layer.
  • R ON R 1 +R 2 +R 3+ R 4+ R 5+ R 6+ R 7+ R 8+ R 9+ R 10
  • R 1 denotes a contact resistance of a drain electrode 50
  • R 2 denotes a contact resistance between the drain electrode 50 and an N-Type impurity layer 52
  • R 3 denotes a resistance of N drain substrate 54
  • R 4 , R 5 and R 6 denote resistances of N drain region 56 respectively
  • R 7 denotes a resistance of P-Type diffusion region 58 for forming a channel
  • R 8 denotes a resistance of N-type source 60
  • R 9 denotes a contact resistance between the N-Type source 60 and a source electrode 62
  • R 10 denotes a resistance of the source electrode 62 .
  • the method by which the N-Type impurity layer is formed is complex because an oxide film adhered to the back surface of the N drain substrate 54 and a diffusion layer having an opposite conductive type (P) to that of the N drain substrate 54 must be removed before the N-type impurity layer 52 is formed.
  • a semiconductor device for household use is demanded with a withstanding voltage more than 100V, normally more than 200V. It is a necessary to make a resistance of a epitaxial layer (the N drain region 56 ) formed on the N drain substrate 54 high to get the withstanding voltage. Therefore, the ratio of the resistance of the N drain substrate 54 to the resistance of the epitaxial layer becomes small.
  • a semiconductor device for a motor vehicle is demanded with a withstanding voltage of at most 50-60V.
  • the resistance of the epitaxial layer is relatively low, and the ratio of the resistance of N drain substrate 54 to the resistance of the epitaxial layer becomes large. Therefore, in the semiconductor device for a motor vehicle, it is effective to reduce the resistance of the N drain substrate 54 for reducing the ON-resistance.
  • the N drain substrate 54 is warped by heat generated in a step that the N-Type impurity layer 52 is formed when the thickness t n of the N drain substrate 54 is too thin.
  • the thickness t n needs to be thick to keep the strength thereof. Therefore, the resistance R 3 of the N drain substrate 54 becomes high, and thus the ON-resistance also becomes high.
  • the technique by which the concentration of antimony (Sb) as a impurity in the N drain substrate 54 is heightened and the resistivity is diminished, may be adopted so as to reduce the resistance R 3 of the N drain substrate 54 .
  • the barrier height of the gold for an P-type silicon substrate is 0.2 eV, and therefore so a good ohmic contact between those can be obtained.
  • the barrier height of the gold for an N-type silicon substrate is relatively high, 0.8 eV, the contact between those becomes a schottky contact and may have undesirable diode character.
  • An object of this invention is to reduce the ON-resistance of a semiconductor device.
  • Another object of this invention is to get a good ohmic contact.
  • a still further object of this invention is to provide a thin semiconductor device having the advantage of small stress from a package and easy wire bonding.
  • a semiconductor device includes an N-type semi-conductor substrate including arsenic as an impurity and having a ground surface formed on one surface thereof, said ground surface having concavo-convex irregularities, a first electrode formed on another surface other than said one surface of said N-type semiconductor substrate, a second electrode formed on said ground surface and ohmically contacted with said N-type semiconductor substrate through said ground surface, and a semiconductor element formed in said N-type semiconductor substrate and in which an electric current flows between said first electrode and said second electrode during an ON-state thereof.
  • FIG. 1 is a sectional view of a semiconductor device of this invention
  • FIG. 2A-2C are sectional views showing the sequence of processes of the semiconductor device of this of this invention.
  • FIG. 3 is a side view for explaining a surface grinding proceeding
  • FIG. 4 is a side view for explaining a lapping grinding proceeding
  • FIG. 5 shows a relationship between the thickness t and destructive strength
  • FIG. 6 is a sectional view for explaining a load test
  • FIG. 7 shows a relationship between the granularity of a grindstone and warp of the silicon substrate
  • FIG. 8 shows a relationship between the impurity concentration and the contact resistance
  • FIG. 9 shows a relationship between V DS and I DS of power MOS FET
  • FIG. 10 shows a relationship between V F and the concentration of As in the silicon substrate
  • FIG. 11 shows a relationship between the concentration of As and the value of the leak current
  • FIG. 12 shows a relationship between the thickness t and shearing stress
  • FIG. 13 is a sectional view of a semiconductor device of the prior art
  • FIG. 14 shows a relationship between the granularity and surface roughness
  • FIG. 15 shows a relationship between the granularity and an ON-resistance.
  • FIG. 1 shows an N-type drain region 2 formed on a silicon substrate 1 which is doped with As (arsenic) formed by crystallizing melted silicon that has As therein.
  • a P-type region 4 is formed in the N-type drain region 2 for forming a channel.
  • An N-type source region 6 is formed in the P-type region 4 .
  • a polycrystalline silicon gate 10 is formed on the N-type drain region 2 and the P-type region 4 through an oxide film (SiO 2 ) 8 .
  • a source electrode 12 is formed on the oxide film 8 and electrically connected with the P-type region 4 and the N-type source region 6 .
  • An ohmic electrode 26 is formed on a ground surface 22 which is formed on a back surface of the silicon substrate 1 .
  • the prior art used Sb (antimony) as an N-type impurity.
  • Sb antimony
  • the concentration of Sb could not be more than 5 ⁇ 10 18 cm ⁇ 3 owing to its limitation of solution.
  • the inventors have solved this problem by including As in the silicon substrate 1 as the N-type impurity. As has a higher limitation of solution than Sb and therefore solves this problem.
  • the concentration of As is set within a range between 7 ⁇ 10 18 cm ⁇ 3 ⁇ 1 ⁇ 10 21 cm ⁇ 3 Therefore, the contact resistance between the silicon substrate 1 and the ohmic electrode 26 can be reduced sufficient to avoid a schottky contact and get an ohmic contact.
  • the ground surface 22 has been ground to have a concavo-convex surface which has many coarse surface irregularities. Therefore, the ohmic electrode 26 can be firmly adhered to the ground surface 22 because the ground surface 22 has a suitable concavo-convex surface.
  • FIG. 2A-2C show the sequence of the process.
  • a silicon crystal is formed by a CZ (Czochralski) method, where As is added as a dopant in a melted silicon.
  • the silicon substrate 1 is formed by slicing the silicon crystal. Therefore the silicon substrate 1 has As a solid solution, the concentration of As being 7 ⁇ 10 18 ⁇ 1 ⁇ 10 21 cm ⁇ 3 , and resistivity of the silicon wafer is less than 0.008 ⁇ cm.
  • FIG. 2A shows the N-type drain region 2 having P (phosphorus) as an impurity and being grown on a main surface of the silicon substrate 1 by an epitaxial growth method.
  • the oxide film (SiO 2 ) 8 is formed on a surface of the N-type drain region 2 .
  • the polycrystalline silicon is deposited on the oxide film 8 by an LPCVD (low pressure chemical vapor deposition) technique.
  • P (phosphorus) is introduced in the polycrystalline silicon, and the polycrystalline silicon is locally etched to form the polycrystalline silicon gate 10 .
  • the polycrystalline silicon gate 10 is oxidized, and P-type impurities such as B (boron), Al (aluminium), Ga (gallium) or the like are diffused into the N-type drain region 2 by using this polycrystalline silicon gate 10 as a mask for forming the P-type region 4 .
  • a portion of the P-type region 4 becomes a channel region.
  • the N-type source region 6 is formed by locally diffusing N-type impurities such as As, P (phosphorus) or the like into the P-type region 4 .
  • Windows are then opened in the oxide film 8 and Al—Si is deposited by a sputtering method for forming the source electrode 12 , so that the source electrode 12 is connected to both the P-type region 4 and the N-type source region 6 .
  • a device layer 14 consists of the P-type region 4 , the N-type source region 6 , the oxide film 8 , the polycrystalline silicon gate 10 , and the source electrode 12 .
  • a passivation film such as a plasma-SiN or the like may be formed on the source electrode 12 for stabilizing a surface of the device layer 14 .
  • a by-product layer 16 such as a polycrystalline silicon, a silicon oxide (SiO 2 ) or the like, is spontaneously formed on another (back) surface of the silicon substrate 1 while the aforementioned device is being manufactured.
  • the another surface of the silicon substrate 1 on which the by-product layer 16 is formed thereon is ground by a surface grinding (SG) proceeding for removing the by-product layer 16 .
  • the surface grinding is carried out by using a grindstone 18 as shown in FIG. 3 .
  • the granularity of the grindstone 18 is between No. 300-No. 500.
  • a surface of the device layer 14 is covered with a adhesive film (not shown) and the device layer 14 is fixed by a vacuum chuck 20 .
  • FIG. 2B shows the by-product layer 16 removed by the grinding, and a ground surface 22 being formed.
  • the thickness t from one surface of the device layer 14 to the another surface of the silicon substrate 1 is 200-450 ⁇ m. After grinding, the whole device is washed by super pure water.
  • the silicon crystal of the another surface of the silicon substrate 1 is damaged by the grinding. This damage destroys some part of the crystalline structure of the silicon substrate, and should therefore be avoided. It also decreases the destruction strength.
  • the depth of this damaged layer is only 1-2 ⁇ m if the surface grinding device of FIG. 3 is used.
  • FIG. 5 shows a graph of depth of the damaged layer. Because the depth of the damaged layer is shallow, the destruction strength of this device is still between 1.0-1.6 kg.
  • FIG. 6 shows a load test where the destruction strength is defined as a maximum load when a chip destroyed. The load test is carried out in such a way that the center of the chip is supported at its both ends and has a load applied thereon by a load piece 24 .
  • FIG. 4 shows the lapping grinding is carried out in the condition which the device is fixed on upper surface plate 30 by paraffin glue and abrasives (a mix of abrasives No. 800 and No. 1200 of SiC) are supplied between the device and a lower surface plate 32 .
  • abrasives a mix of abrasives No. 800 and No. 1200 of SiC
  • FIG. 7 shows that when the granularity of the grindstone 18 is No. 300-No. 500, the warping of the silicon substrate 1 can be reduced. If the granularity is finer than No. 500, however the warp becomes larger. If the granularity is coarser than No. 300, the possibility which of breaking of the silicon substrate 1 is increased.
  • the reason why the warping is reduce is that the coarser the granularity is, the more stress in the silicon substrate is dispersed.
  • FIG. 14 shows a relationship between the granularity of the grindstone 18 and surface roughness Ra.
  • the surface roughness Ra is in a range between 0.3-0.6 ⁇ m.
  • the surface roughness Ra is almost 0,2 ⁇ m.
  • the surface roughness Ra becomes almost 0 ⁇ m. It is to be noted that surface roughness Ra of the silicon substrate 1 which is polished up is also almost 0 ⁇ m.
  • FIG. 15 shows a relationship between the granularity of the grindstone 18 and an ON-resistance.
  • the ON-resistance becomes low.
  • barrier height of the ohmic electrode 26 for the silicon substrate 1 becomes high, and the contact resistance between the ohmic electrode 26 and the silicon substrate 1 .
  • the granularity is a range between No. 320-No. 600 to reduce the ON-resistance.
  • FIG. 2C snows that after the spontaneously formed by product layer 16 (not shown) has been removed by a wet etching or an RF etching, and an ohmic electrode 26 is formed on the ground surface 22 by a sputtering method.
  • the ohmic electrode 26 acts as a drain electrode.
  • the ohmic electrode 26 is a multilayer electrode consisting of Ti—Ni—Au layers.
  • electrode material such as Ti (titanium), V (vanadium), Cr (chromium), Ni (nickel) or the like
  • impurity concentration in the silicon substrate 1 more than 5 ⁇ 10 18 cm ⁇ 3 , preferably, more than 7 ⁇ 10 18 cm ⁇ 3 so as to make an ohmic contact with the electrode material.
  • the barrier height ⁇ B of the electrode material for silicon is 0.4-0.6 eV. As shown in FIG.
  • the contact resistance between the electrode material and the silicon substrate 1 begins to rapidly be reduced, and if the impurity concentration is more than 7 ⁇ 10 18 cm ⁇ 3 , the contact resistance becomes less than 10 ⁇ 3 ⁇ cm 2 .
  • FIG. 9 shows a relationship between V DS (voltage between the source and the drain) and I DS (current between the source and drain) of this power MOS FET.
  • Voltage of the gate V G is a parameter shown in Figure as being used as an index so as to judge whether the contact is a schottky contact.
  • FIG. 10 shows a relationship between this calculated V F and a concentration of As in the silicon substrate 1 .
  • V F becomes substantially 0(zero) and the contact is an ohmic contact.
  • the upper limitation of the concentration of As which is included in the silicon substrate 1 is its limitation of solution. This limitation is found by measuring the value of leakage current through the P-N junction.
  • FIG. 11 shows a relationship between the concentration of As and the value of the leakage current through the P-N junction.
  • a P-type impurity such as B(boron) or the like is diffused in an N-type silicon substrate including As as an impurity.
  • the concentration of As is higher than its limitation of solution, the crystallinity of silicon is disordered and leakage current flows through the P-N junction. Therefore, the concentration when the leakage current begins to flow is defined as the value of its limitation of solution. As shown in FIG. 11 , the limitation of solution is 1 ⁇ 10 21 cm ⁇ 3 .
  • the chip which was manufactured by abovementioned manufacturing steps is molded by silicone resin, and an IC package is formed.
  • this molding step because a thickness of the chip is thin, as shown in FIG. 12 , the shearing stress becomes low. Consequently, the stress of the IC package is relaxed.
  • a lead frame (not shown) is bonded to the source electrode 12 with a wire, the wire-bonding work becomes easy because the height of the lead frame and the source electrode 12 are similar and therefore these makes a low step.
  • the present invention has been described with reference to the abovementioned embodiment, but the present invention is not limited to this embodiment and can be modified without departing from the spirit or concept of the present invention.
  • the present invention may be applied to an IGBT (Insulated Gate Bipolar Transistor), SIT (Static Induction Transistor), SI (State Induction) thyristor or the like other than the power MOSFET.
  • IGBT Insulated Gate Bipolar Transistor
  • SIT Static Induction Transistor
  • SI State Induction

Abstract

A semiconductor device including an N-type semiconductor substrate which includes arsenic as an impurity, a first electrode formed on a main surface of the N-type semiconductor substrate, a ground surface formed on another surface of the N-type semiconductor substrate, a second electrode formed on the ground surface and ohmically-contacted with the N-type semiconductor substrate, a semiconductor element formed in the N-type semiconductor substrate and flowing current between the first electrode and the second electrode during ON-state thereof. The device has a reduced ON-resistance thereof.

Description

    CROSS-REFERENCE TO RELATED APPLICATIONS
  • This application is a divisional of U.S. Ser. No. 10/880,048 filed Jun. 29, 2004, which is a divisional of U.S. Ser. No. 10/880,044 filed Jun. 29, 2004, which is a divisional of U.S. Ser. No. 10/651,277 filed Aug. 28, 2003, which is a divisional of Ser. No. 10/283,981 filed Oct. 30, 2002, now U.S. Pat. No. 6,649,478 which is a divisional of Ser. No. 08/962,322 filed Oct. 31, 1997, now U.S. Pat. No. 6,498,366 which is a divisional of Ser. No. 08/409,900 filed Mar. 22, 1995 now U.S. Pat. No. 5,689,130 which is a continuation of Ser. No. 07/953,766 filed Sep. 30, 1992, ABD, which is a divisional of Ser. No. 07/652,920 filed Feb. 8, 1991 now U.S. Pat. No. 5,242,862. This application claims the benefit of JPSN P2-33367, filed Feb. 14, 1990. The disclosure of the above applications are incorporated herein by reference.
    • BACKGROUND OF THE INVENTION
  • 1. Field of the Invention
  • This invention relates to a semiconductor device which has a low ON-resistance, and further, to a method of manufacturing such a semiconductor device.
  • 2. Description of the Related Art
  • Many kinds of methods of manufacturing for reducing an ON-resistance of a semiconductor device have been known. For example, Japanese Unexamined Patent Publication 1-169970 discloses a method which an N-type impurity layer is formed in a back surface of a drain substrate so as to reduce a contact resistance between the drain substrate and a drain electrode. Japanese Examined Patent Publication 58-45814 discloses a method of manufacturing the semiconductor device which has a good ohmic contact between the drain substrate and the drain electrode. The device has a multilayer metal electrode on a back surface of a drain substrate. The multilayer metal electrode consists of layers having a gold layer as a main layer.
  • As shown in FIG. 13, the ON-resistance of a field effect transistor (FET) is represented by the following equation:
    R ON =R1+R2+R3+R4+R5+R6+R7+R8+R9+R10
    wherein, R1 denotes a contact resistance of a drain electrode 50; R2 denotes a contact resistance between the drain electrode 50 and an N-Type impurity layer 52; R3 denotes a resistance of N drain substrate 54; R4, R5 and R6 denote resistances of N drain region 56 respectively; R7 denotes a resistance of P-Type diffusion region 58 for forming a channel; R8 denotes a resistance of N-type source 60; R9 denotes a contact resistance between the N-Type source 60 and a source electrode 62; and R10 denotes a resistance of the source electrode 62.
  • However, such a conventional method of manufacturing the semiconductor device has many problems. For example, the method by which the N-Type impurity layer is formed is complex because an oxide film adhered to the back surface of the N drain substrate 54 and a diffusion layer having an opposite conductive type (P) to that of the N drain substrate 54 must be removed before the N-type impurity layer 52 is formed.
  • A semiconductor device for household use is demanded with a withstanding voltage more than 100V, normally more than 200V. It is a necessary to make a resistance of a epitaxial layer (the N drain region 56) formed on the N drain substrate 54 high to get the withstanding voltage. Therefore, the ratio of the resistance of the N drain substrate 54 to the resistance of the epitaxial layer becomes small. On the contrary, a semiconductor device for a motor vehicle is demanded with a withstanding voltage of at most 50-60V. The resistance of the epitaxial layer is relatively low, and the ratio of the resistance of N drain substrate 54 to the resistance of the epitaxial layer becomes large. Therefore, in the semiconductor device for a motor vehicle, it is effective to reduce the resistance of the N drain substrate 54 for reducing the ON-resistance.
  • The resistance R3 of the N drain substrate 54 is represented by the following equation:
    R3=ρN ×t n /S
    wherein, ρN denotes resistivity of the N drain substrate 54; tn denotes a thickness of the N drain substrate 54; and S denotes a cross section of the N drain substrate 54. It is necessary to reduce the thickness tn of the N drain substrate 54 so as to reduce this resistance R3. However, the thickness tn of the N drain substrate 54 for forming the N-Type impurity layer 52 is determined in accordance with a thickness of a silicon wafer. The reason is that the N drain substrate 54 is warped by heat generated in a step that the N-Type impurity layer 52 is formed when the thickness tn of the N drain substrate 54 is too thin. To get a wafer of large diameter, the thickness tn needs to be thick to keep the strength thereof. Therefore, the resistance R3 of the N drain substrate 54 becomes high, and thus the ON-resistance also becomes high.
  • The technique by which the concentration of antimony (Sb) as a impurity in the N drain substrate 54 is heightened and the resistivity is diminished, may be adopted so as to reduce the resistance R3 of the N drain substrate 54. However, it is impossible to make the resistance R3 less than 0.01Ω·cm because of the limitation of the amount solution of Sb which can be in the solution.
  • Moreover, since it is impossible to make the impurity concentration in the substrate high because of the limitation of solution, it is difficult to get a good ohmic contact between an N-type substrate and an electrode.
  • On the other hand, in the method which utilizes gold as an electrode material, the barrier height of the gold for an P-type silicon substrate is 0.2 eV, and therefore so a good ohmic contact between those can be obtained. However, since the barrier height of the gold for an N-type silicon substrate is relatively high, 0.8 eV, the contact between those becomes a schottky contact and may have undesirable diode character.
  • Moreover, when an overall thickness is thick, stress from a package and a step between a lead frame and the source electrode 62 becomes higher. Therefore, the wire bonding work becomes very difficult. Also, the cost of gold is very high.
  • Techniques other than the aforementioned techniques have also been known. The technique which is disclosed in Japanese Unexamined Patent Publication 57-15420 suggests that a back surface of a silicon substrate is ground to improve adherence between the back surface and a collector electrode formed on the back surface. The technique which is disclosed in “IEEE ELECTRON DEVICE LETTERS, VOL. 10, NO. 3 MARCH 1989, P101-103” suggests that a 0.004Ω·cm arsenic-doped silicon substrate is used.
    • SUMMARY OF THE INVENTION
  • An object of this invention is to reduce the ON-resistance of a semiconductor device.
  • Another object of this invention is to get a good ohmic contact.
  • A still further object of this invention is to provide a thin semiconductor device having the advantage of small stress from a package and easy wire bonding.
  • To accomplish the above objects, a semiconductor device according to this invention includes an N-type semi-conductor substrate including arsenic as an impurity and having a ground surface formed on one surface thereof, said ground surface having concavo-convex irregularities, a first electrode formed on another surface other than said one surface of said N-type semiconductor substrate, a second electrode formed on said ground surface and ohmically contacted with said N-type semiconductor substrate through said ground surface, and a semiconductor element formed in said N-type semiconductor substrate and in which an electric current flows between said first electrode and said second electrode during an ON-state thereof.
    • BRIEF DESCRIPTION OF THE DRAWINGS
  • FIG. 1 is a sectional view of a semiconductor device of this invention;
  • FIG. 2A-2C are sectional views showing the sequence of processes of the semiconductor device of this of this invention;
  • FIG. 3 is a side view for explaining a surface grinding proceeding;
  • FIG. 4 is a side view for explaining a lapping grinding proceeding;
  • FIG. 5 shows a relationship between the thickness t and destructive strength;
  • FIG. 6 is a sectional view for explaining a load test;
  • FIG. 7 shows a relationship between the granularity of a grindstone and warp of the silicon substrate;
  • FIG. 8 shows a relationship between the impurity concentration and the contact resistance;
  • FIG. 9 shows a relationship between V DS and IDS of power MOS FET;
  • FIG. 10 shows a relationship between V F and the concentration of As in the silicon substrate;
  • FIG. 11 shows a relationship between the concentration of As and the value of the leak current;
  • FIG. 12 shows a relationship between the thickness t and shearing stress;
  • FIG. 13 is a sectional view of a semiconductor device of the prior art;
  • FIG. 14 shows a relationship between the granularity and surface roughness; and
  • FIG. 15 shows a relationship between the granularity and an ON-resistance.
    • DESCRIPTION OF THE PREFERRED EMBODIMENTS
  • The preferred embodiments of this invention will be described with reference to the drawings. The embodiments are suitable for a semiconductor device for a motor vehicle.
  • FIG. 1 shows an N-type drain region 2 formed on a silicon substrate 1 which is doped with As (arsenic) formed by crystallizing melted silicon that has As therein. A P-type region 4 is formed in the N-type drain region 2 for forming a channel. An N-type source region 6 is formed in the P-type region 4. A polycrystalline silicon gate 10 is formed on the N-type drain region 2 and the P-type region 4 through an oxide film (SiO2) 8. A source electrode 12 is formed on the oxide film 8 and electrically connected with the P-type region 4 and the N-type source region 6. An ohmic electrode 26 is formed on a ground surface 22 which is formed on a back surface of the silicon substrate 1.
  • Here, the prior art used Sb (antimony) as an N-type impurity. However, the concentration of Sb could not be more than 5×1018cm−3 owing to its limitation of solution. The inventors have solved this problem by including As in the silicon substrate 1 as the N-type impurity. As has a higher limitation of solution than Sb and therefore solves this problem. The concentration of As is set within a range between 7×1018 cm−3−1×1021 cm−3 Therefore, the contact resistance between the silicon substrate 1 and the ohmic electrode 26 can be reduced sufficient to avoid a schottky contact and get an ohmic contact. Since the concentration of As is more than 7×1018 cm−3, a good ohmic contact can be obtained for almost all electrode materials. Moreover, the resistivity of the silicon substrate 1 is also diminished because of the higher concentration of As included in the silicon substrate 1 as an impurity. Consequently, the resistance R3 of the silicon substrate 1 is also reduced. The ground surface 22 has been ground to have a concavo-convex surface which has many coarse surface irregularities. Therefore, the ohmic electrode 26 can be firmly adhered to the ground surface 22 because the ground surface 22 has a suitable concavo-convex surface.
  • The process of forming the aforementioned semiconductor device of the embodiment of this invention will now be described with reference to FIG. 2A-2C. FIG. 2A-2C show the sequence of the process. A silicon crystal is formed by a CZ (Czochralski) method, where As is added as a dopant in a melted silicon. The silicon substrate 1 is formed by slicing the silicon crystal. Therefore the silicon substrate 1 has As a solid solution, the concentration of As being 7×1018−1×1021 cm−3, and resistivity of the silicon wafer is less than 0.008Ω·cm. FIG. 2A shows the N-type drain region 2 having P (phosphorus) as an impurity and being grown on a main surface of the silicon substrate 1 by an epitaxial growth method. The oxide film (SiO2) 8 is formed on a surface of the N-type drain region 2. The polycrystalline silicon is deposited on the oxide film 8 by an LPCVD (low pressure chemical vapor deposition) technique. P (phosphorus) is introduced in the polycrystalline silicon, and the polycrystalline silicon is locally etched to form the polycrystalline silicon gate 10. The polycrystalline silicon gate 10 is oxidized, and P-type impurities such as B (boron), Al (aluminium), Ga (gallium) or the like are diffused into the N-type drain region 2 by using this polycrystalline silicon gate 10 as a mask for forming the P-type region 4. A portion of the P-type region 4 becomes a channel region. The N-type source region 6 is formed by locally diffusing N-type impurities such as As, P (phosphorus) or the like into the P-type region 4. Windows are then opened in the oxide film 8 and Al—Si is deposited by a sputtering method for forming the source electrode 12, so that the source electrode 12 is connected to both the P-type region 4 and the N-type source region 6. Here, a device layer 14 consists of the P-type region 4, the N-type source region 6, the oxide film 8, the polycrystalline silicon gate 10, and the source electrode 12. Moreover, a passivation film such as a plasma-SiN or the like may be formed on the source electrode 12 for stabilizing a surface of the device layer 14.
  • During this process, a by-product layer 16, such as a polycrystalline silicon, a silicon oxide (SiO2) or the like, is spontaneously formed on another (back) surface of the silicon substrate 1 while the aforementioned device is being manufactured. The another surface of the silicon substrate 1 on which the by-product layer 16 is formed thereon is ground by a surface grinding (SG) proceeding for removing the by-product layer 16. The surface grinding is carried out by using a grindstone 18 as shown in FIG. 3. The granularity of the grindstone 18 is between No. 300-No. 500. In this embodiment, a surface of the device layer 14 is covered with a adhesive film (not shown) and the device layer 14 is fixed by a vacuum chuck 20.
  • FIG. 2B shows the by-product layer 16 removed by the grinding, and a ground surface 22 being formed. In this condition, the thickness t from one surface of the device layer 14 to the another surface of the silicon substrate 1 is 200-450 μm. After grinding, the whole device is washed by super pure water.
  • The silicon crystal of the another surface of the silicon substrate 1 is damaged by the grinding. This damage destroys some part of the crystalline structure of the silicon substrate, and should therefore be avoided. It also decreases the destruction strength. However, the depth of this damaged layer is only 1-2 μm if the surface grinding device of FIG. 3 is used. FIG. 5 shows a graph of depth of the damaged layer. Because the depth of the damaged layer is shallow, the destruction strength of this device is still between 1.0-1.6 kg. FIG. 6 shows a load test where the destruction strength is defined as a maximum load when a chip destroyed. The load test is carried out in such a way that the center of the chip is supported at its both ends and has a load applied thereon by a load piece 24.
  • If the another surface of the silicon substrate 1 is ground by lapping grinding instead of surface grinding, the depth of the damaged layer is 6-7 μm, and the destruction strength of this device becomes 0.3-0.6 kg (shown in FIG. 5). FIG. 4 shows the lapping grinding is carried out in the condition which the device is fixed on upper surface plate 30 by paraffin glue and abrasives (a mix of abrasives No. 800 and No. 1200 of SiC) are supplied between the device and a lower surface plate 32. As understood by comparing the two lines in FIG. 5, surface grinding will make the destruction strength stronger than lapping grinding.
  • FIG. 7 shows that when the granularity of the grindstone 18 is No. 300-No. 500, the warping of the silicon substrate 1 can be reduced. If the granularity is finer than No. 500, however the warp becomes larger. If the granularity is coarser than No. 300, the possibility which of breaking of the silicon substrate 1 is increased.
  • The reason why the warping is reduce is that the coarser the granularity is, the more stress in the silicon substrate is dispersed.
  • FIG. 14 shows a relationship between the granularity of the grindstone 18 and surface roughness Ra. When the granularity is No. 320, the surface roughness Ra is in a range between 0.3-0.6 μm. When the granularity is No. 600, the surface roughness Ra is almost 0,2 μm. When the granularity is No. 4000, the surface roughness Ra becomes almost 0 μm. It is to be noted that surface roughness Ra of the silicon substrate 1 which is polished up is also almost 0 μm.
  • FIG. 15 shows a relationship between the granularity of the grindstone 18 and an ON-resistance. As shown in FIG. 15, when the granularity is coarser, the ON-resistance becomes low. The reason is that when the granularity is coarser, barrier height of the ohmic electrode 26 for the silicon substrate 1 becomes high, and the contact resistance between the ohmic electrode 26 and the silicon substrate 1. It is desirable that the granularity is a range between No. 320-No. 600 to reduce the ON-resistance.
  • FIG. 2C snows that after the spontaneously formed by product layer 16 (not shown) has been removed by a wet etching or an RF etching, and an ohmic electrode 26 is formed on the ground surface 22 by a sputtering method. The ohmic electrode 26 acts as a drain electrode. In this embodiment, the ohmic electrode 26 is a multilayer electrode consisting of Ti—Ni—Au layers. When electrode material, such as Ti (titanium), V (vanadium), Cr (chromium), Ni (nickel) or the like, is adopted, it is necessary to make an impurity concentration in the silicon substrate 1 more than 5×1018 cm−3, preferably, more than 7×1018 cm−3 so as to make an ohmic contact with the electrode material. The barrier height ΦB of the electrode material for silicon is 0.4-0.6 eV. As shown in FIG. 8, if the impurity concentration is more than 5×1018cm−3, the contact resistance between the electrode material and the silicon substrate 1 begins to rapidly be reduced, and if the impurity concentration is more than 7×1018cm−3, the contact resistance becomes less than 10−3Ω·cm2.
  • FIG. 9 shows a relationship between V DS (voltage between the source and the drain) and I DS (current between the source and drain) of this power MOS FET. Voltage of the gate V G is a parameter shown in Figure as being used as an index so as to judge whether the contact is a schottky contact.
  • FIG. 10 shows a relationship between this calculated V F and a concentration of As in the silicon substrate 1. As shown in FIG. 10, when the concentration of As is more than 7×1018 cm−3, V F becomes substantially 0(zero) and the contact is an ohmic contact.
  • The upper limitation of the concentration of As which is included in the silicon substrate 1 is its limitation of solution. This limitation is found by measuring the value of leakage current through the P-N junction.
  • FIG. 11 shows a relationship between the concentration of As and the value of the leakage current through the P-N junction. Before the value of the leakage current is measured, to form P-N junction, a P-type impurity such as B(boron) or the like is diffused in an N-type silicon substrate including As as an impurity. When the concentration of As is higher than its limitation of solution, the crystallinity of silicon is disordered and leakage current flows through the P-N junction. Therefore, the concentration when the leakage current begins to flow is defined as the value of its limitation of solution. As shown in FIG. 11, the limitation of solution is 1×1021 cm−3.
  • The chip which was manufactured by abovementioned manufacturing steps is molded by silicone resin, and an IC package is formed. In this molding step, because a thickness of the chip is thin, as shown in FIG. 12, the shearing stress becomes low. Consequently, the stress of the IC package is relaxed. Moreover, when a lead frame (not shown) is bonded to the source electrode 12 with a wire, the wire-bonding work becomes easy because the height of the lead frame and the source electrode 12 are similar and therefore these makes a low step.
  • The present invention has been described with reference to the abovementioned embodiment, but the present invention is not limited to this embodiment and can be modified without departing from the spirit or concept of the present invention. For example, the present invention may be applied to an IGBT (Insulated Gate Bipolar Transistor), SIT (Static Induction Transistor), SI (State Induction) thyristor or the like other than the power MOSFET. These semiconductor elements flow current in a vertical direction (a direction of a thickness of a substrate) and an electrode formed on N-type silicon substrate.

Claims (4)

1. A method of manufacturing a vertical type semiconductor device comprising:
preparing a semiconductor wafer which has a heavily doped semiconductor substrate doped with arsenic as an impurity and a lightly doped semiconductor layer disposed over said semiconductor substrate;
forming a semiconductor element at a surface portion of said semiconductor layer;
forming a first metal layer for a first electrode of said semiconductor element over said surface portion of said semiconductor layer;
grinding a back of said semiconductor substrate to thin said semiconductor substrate and roughen a back surface of said semiconductor substrate, said grinding being performed until a thickness from a surface of said first metal layer to said back surface is 200-450 microns;
performing a RF etching upon said back surface; and
forming on said back surface a second metal layer for a second electrode of said semiconductor element.
2. A method of manufacturing a vertical type semiconductor device according to claim 1, wherein said forming of said second metal layer includes forming by a sputtering method.
3. A method of manufacturing a vertical type semiconductor device comprising:
preparing a semiconductor wafer which has a heavily doped semiconductor substrate and a lightly doped semiconductor layer disposed over said semiconductor substrate;
forming a semiconductor element at a surface portion of said semiconductor layer;
forming a first metal layer for a first electrode of said semiconductor element over said surface portion of said semiconductor layer;
grinding a back of said semiconductor substrate to thin said semiconductor substrate and roughen a back surface of said semiconductor substrate;
performing a RF etching upon said back surface; and
forming on said back surface a second metal layer for a second electrode of said semiconductor element.
4. A method of manufacturing a vertical type semiconductor device according to claim 3, wherein said forming of said second metal layer includes forming by a sputtering method.
US11/140,756 1990-02-14 2005-05-31 Semiconductor device and method of manufacturing same Abandoned US20050227438A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US11/140,756 US20050227438A1 (en) 1990-02-14 2005-05-31 Semiconductor device and method of manufacturing same

Applications Claiming Priority (11)

Application Number Priority Date Filing Date Title
JPP2-33367 1990-02-14
JP2033367A JP2513055B2 (en) 1990-02-14 1990-02-14 Method for manufacturing semiconductor device
US07/652,920 US5242862A (en) 1990-02-14 1991-02-08 Semiconductor device and method of manufacturing same
US95376692A 1992-09-30 1992-09-30
US08/409,900 US5689130A (en) 1990-02-14 1995-03-22 Vertical semiconductor device with ground surface providing a reduced ON resistance
US08/962,322 US6498366B1 (en) 1990-02-14 1997-10-31 Semiconductor device that exhibits decreased contact resistance between substrate and drain electrode
US10/283,981 US6649478B2 (en) 1990-02-14 2002-10-30 Semiconductor device and method of manufacturing same
US10/651,277 US6903417B2 (en) 1990-02-14 2003-08-28 Power semiconductor device
US10/880,044 US7064033B2 (en) 1990-02-14 2004-06-29 Semiconductor device and method of manufacturing same
US10/880,048 US6949434B2 (en) 1990-02-14 2004-06-29 Method of manufacturing a vertical semiconductor device
US11/140,756 US20050227438A1 (en) 1990-02-14 2005-05-31 Semiconductor device and method of manufacturing same

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US10/880,048 Division US6949434B2 (en) 1990-02-14 2004-06-29 Method of manufacturing a vertical semiconductor device

Publications (1)

Publication Number Publication Date
US20050227438A1 true US20050227438A1 (en) 2005-10-13

Family

ID=12384616

Family Applications (10)

Application Number Title Priority Date Filing Date
US07/652,920 Expired - Lifetime US5242862A (en) 1990-02-14 1991-02-08 Semiconductor device and method of manufacturing same
US08/409,900 Expired - Lifetime US5689130A (en) 1990-02-14 1995-03-22 Vertical semiconductor device with ground surface providing a reduced ON resistance
US08/473,775 Expired - Lifetime US5663096A (en) 1990-02-14 1995-06-06 Method of manufacturing a vertical semiconductor device with ground surface providing a reduced ON resistance
US08/962,322 Expired - Fee Related US6498366B1 (en) 1990-02-14 1997-10-31 Semiconductor device that exhibits decreased contact resistance between substrate and drain electrode
US08/962,278 Expired - Fee Related US5994187A (en) 1990-02-14 1997-10-31 Method of manufacturing a vertical semiconductor device
US10/283,981 Expired - Fee Related US6649478B2 (en) 1990-02-14 2002-10-30 Semiconductor device and method of manufacturing same
US10/651,277 Expired - Fee Related US6903417B2 (en) 1990-02-14 2003-08-28 Power semiconductor device
US10/880,044 Expired - Fee Related US7064033B2 (en) 1990-02-14 2004-06-29 Semiconductor device and method of manufacturing same
US10/880,048 Expired - Fee Related US6949434B2 (en) 1990-02-14 2004-06-29 Method of manufacturing a vertical semiconductor device
US11/140,756 Abandoned US20050227438A1 (en) 1990-02-14 2005-05-31 Semiconductor device and method of manufacturing same

Family Applications Before (9)

Application Number Title Priority Date Filing Date
US07/652,920 Expired - Lifetime US5242862A (en) 1990-02-14 1991-02-08 Semiconductor device and method of manufacturing same
US08/409,900 Expired - Lifetime US5689130A (en) 1990-02-14 1995-03-22 Vertical semiconductor device with ground surface providing a reduced ON resistance
US08/473,775 Expired - Lifetime US5663096A (en) 1990-02-14 1995-06-06 Method of manufacturing a vertical semiconductor device with ground surface providing a reduced ON resistance
US08/962,322 Expired - Fee Related US6498366B1 (en) 1990-02-14 1997-10-31 Semiconductor device that exhibits decreased contact resistance between substrate and drain electrode
US08/962,278 Expired - Fee Related US5994187A (en) 1990-02-14 1997-10-31 Method of manufacturing a vertical semiconductor device
US10/283,981 Expired - Fee Related US6649478B2 (en) 1990-02-14 2002-10-30 Semiconductor device and method of manufacturing same
US10/651,277 Expired - Fee Related US6903417B2 (en) 1990-02-14 2003-08-28 Power semiconductor device
US10/880,044 Expired - Fee Related US7064033B2 (en) 1990-02-14 2004-06-29 Semiconductor device and method of manufacturing same
US10/880,048 Expired - Fee Related US6949434B2 (en) 1990-02-14 2004-06-29 Method of manufacturing a vertical semiconductor device

Country Status (2)

Country Link
US (10) US5242862A (en)
JP (1) JP2513055B2 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070111480A1 (en) * 2005-11-16 2007-05-17 Denso Corporation Wafer product and processing method therefor
US20080006856A1 (en) * 2006-06-22 2008-01-10 Fuji Electric Device Technology Co., Ltd Semiconductor device with back surface electrode including a stress relaxation film
US20110039382A1 (en) * 2006-12-07 2011-02-17 Shindengen Electric Manufacturing Co., Ltd. Semiconductor device and method for manufacturing the same
US20130256964A1 (en) * 2012-03-27 2013-10-03 Mitsubishi Electric Corporation Wafer suction method, wafer suction stage, and wafer suction system

Families Citing this family (44)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2513055B2 (en) * 1990-02-14 1996-07-03 日本電装株式会社 Method for manufacturing semiconductor device
JP3412332B2 (en) * 1995-04-26 2003-06-03 株式会社デンソー Semiconductor device
JP3498431B2 (en) * 1995-07-04 2004-02-16 株式会社デンソー Method for manufacturing semiconductor device
US6478977B1 (en) * 1995-09-13 2002-11-12 Hitachi, Ltd. Polishing method and apparatus
US5698474A (en) * 1996-02-26 1997-12-16 Hypervision, Inc. High speed diamond-based machining of silicon semiconductor die in wafer and packaged form for backside emission microscope detection
US6613674B1 (en) 1997-11-12 2003-09-02 Micron Technology, Inc. Semiconductor processing methods of forming integrated circuitry, and methods of forming dynamic random access memory circuitry
US5963406A (en) 1997-12-19 1999-10-05 Leviton Manufacturing Co., Inc. Arc fault detector with circuit interrupter
US6104062A (en) * 1998-06-30 2000-08-15 Intersil Corporation Semiconductor device having reduced effective substrate resistivity and associated methods
JP3339838B2 (en) * 1999-06-07 2002-10-28 ローム株式会社 Semiconductor device and method of manufacturing the same
US6184064B1 (en) * 2000-01-12 2001-02-06 Micron Technology, Inc. Semiconductor die back side surface and method of fabrication
US20070042549A1 (en) * 2000-04-17 2007-02-22 Fairchild Semiconductor Corporation Semiconductor device having reduced effective substrate resistivity and associated methods
FR2818443B1 (en) * 2000-12-20 2003-10-31 Sagem METHOD FOR MANUFACTURING INFRARED MATRIX DETECTOR WITH LIGHTING FROM THE REAR PANEL
DE10205323B4 (en) * 2001-02-09 2011-03-24 Fuji Electric Systems Co., Ltd. Method for producing a semiconductor component
US6630369B2 (en) 2001-07-17 2003-10-07 Ultra Tec Manufacturing, Inc. Sample preparation apparatus and method
US7145254B2 (en) * 2001-07-26 2006-12-05 Denso Corporation Transfer-molded power device and method for manufacturing transfer-molded power device
JP3580293B2 (en) * 2002-03-26 2004-10-20 株式会社デンソー Method for manufacturing semiconductor device
DE10256985B4 (en) * 2001-12-12 2013-01-10 Denso Corporation Method for producing a power semiconductor component
US7169685B2 (en) 2002-02-25 2007-01-30 Micron Technology, Inc. Wafer back side coating to balance stress from passivation layer on front of wafer and be used as die attach adhesive
DK174717B1 (en) * 2002-05-22 2003-10-06 Danfoss Drives As Engine control containing an electronic circuit for protection against inrush currents
US6833556B2 (en) * 2002-08-12 2004-12-21 Acorn Technologies, Inc. Insulated gate field effect transistor having passivated schottky barriers to the channel
US7084423B2 (en) 2002-08-12 2006-08-01 Acorn Technologies, Inc. Method for depinning the Fermi level of a semiconductor at an electrical junction and devices incorporating such junctions
JP3870896B2 (en) * 2002-12-11 2007-01-24 株式会社デンソー Semiconductor device manufacturing method and semiconductor device manufactured thereby
US6879050B2 (en) * 2003-02-11 2005-04-12 Micron Technology, Inc. Packaged microelectronic devices and methods for packaging microelectronic devices
US7529847B2 (en) * 2003-03-20 2009-05-05 Microsoft Corporation Access to audio output via capture service
DE10338078B4 (en) * 2003-08-19 2008-10-16 Infineon Technologies Ag Semiconductor element with improved adhesion properties of the non-metallic surfaces and method for its production
DE10345494B4 (en) * 2003-09-30 2016-04-07 Infineon Technologies Ag Method for processing a thin semiconductor substrate
JP4878738B2 (en) * 2004-04-30 2012-02-15 株式会社ディスコ Semiconductor device processing method
US7384826B2 (en) * 2004-06-29 2008-06-10 International Rectifier Corporation Method of forming ohmic contact to a semiconductor body
US8901699B2 (en) 2005-05-11 2014-12-02 Cree, Inc. Silicon carbide junction barrier Schottky diodes with suppressed minority carrier injection
JP4221012B2 (en) * 2006-06-12 2009-02-12 トヨタ自動車株式会社 Semiconductor device and manufacturing method thereof
US8409347B2 (en) * 2006-07-20 2013-04-02 Sumco Techxiv Corporation Method of dopant injection, N-type silicon single-crystal, doping apparatus and pull-up device
FR2914488B1 (en) * 2007-03-30 2010-08-27 Soitec Silicon On Insulator DOPE HEATING SUBSTRATE
WO2010109572A1 (en) 2009-03-23 2010-09-30 トヨタ自動車株式会社 Semiconductor device
JP5726434B2 (en) * 2010-04-14 2015-06-03 浜松ホトニクス株式会社 Semiconductor photo detector
US9159825B2 (en) 2010-10-12 2015-10-13 Silanna Semiconductor U.S.A., Inc. Double-sided vertical semiconductor device with thinned substrate
US8426888B2 (en) 2010-10-12 2013-04-23 Io Semiconductor, Inc. Vertical semiconductor device with thinned substrate
CN102522326B (en) * 2011-12-14 2014-09-24 杭州立昂微电子股份有限公司 Production method of semiconductor discrete device back side metal suitable for screen printing
US8778735B1 (en) * 2013-06-29 2014-07-15 Alpha & Omega Semiconductor, Inc. Packaging method of molded wafer level chip scale package (WLCSP)
JP2014157957A (en) * 2013-02-18 2014-08-28 Mitsubishi Electric Corp Semiconductor device
JP2014207382A (en) 2013-04-15 2014-10-30 ラピスセミコンダクタ株式会社 Semiconductor device manufacturing method and semiconductor device
US20150118810A1 (en) * 2013-10-24 2015-04-30 Madhur Bobde Buried field ring field effect transistor (buf-fet) integrated with cells implanted with hole supply path
US9620611B1 (en) 2016-06-17 2017-04-11 Acorn Technology, Inc. MIS contact structure with metal oxide conductor
US10170627B2 (en) 2016-11-18 2019-01-01 Acorn Technologies, Inc. Nanowire transistor with source and drain induced by electrical contacts with negative schottky barrier height
US11398434B2 (en) * 2017-09-20 2022-07-26 Mitsubishi Electric Corporation Semiconductor device, and method for manufacturing semiconductor device

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4213818A (en) * 1979-01-04 1980-07-22 Signetics Corporation Selective plasma vapor etching process
US4782028A (en) * 1987-08-27 1988-11-01 Santa Barbara Research Center Process methodology for two-sided fabrication of devices on thinned silicon
US4859626A (en) * 1988-06-03 1989-08-22 Texas Instruments Incorporated Method of forming thin epitaxial layers using multistep growth for autodoping control
US4879250A (en) * 1988-09-29 1989-11-07 The Boeing Company Method of making a monolithic interleaved LED/PIN photodetector array
US4902641A (en) * 1987-07-31 1990-02-20 Motorola, Inc. Process for making an inverted silicon-on-insulator semiconductor device having a pedestal structure
US4985740A (en) * 1989-06-01 1991-01-15 General Electric Company Power field effect devices having low gate sheet resistance and low ohmic contact resistance

Family Cites Families (49)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1053694A (en) 1910-04-29 1913-02-18 Union Paper Company Feeding mechanism for blanking and forming machines.
US1469757A (en) 1921-09-30 1923-10-02 Edward L Sibley Mfg Company In Blanking-out eyelets
US3083926A (en) 1959-06-17 1963-04-02 Herr Equipment Corp Strip handling
US3278813A (en) * 1964-04-22 1966-10-11 Gen Electric Transistor housing containing packed, earthy, nonmetallic, electrically insulating material
US3879230A (en) * 1970-02-07 1975-04-22 Tokyo Shibaura Electric Co Semiconductor device diffusion source containing as impurities AS and P or B
US3858238A (en) * 1970-02-07 1974-12-31 Tokyo Shibaura Electric Co Semiconductor devices containing as impurities as and p or b and the mehtod of manufacturing the same
SE367138B (en) 1972-10-05 1974-05-20 Asea Ab
US4027383A (en) * 1974-01-24 1977-06-07 Massachusetts Institute Of Technology Integrated circuit packaging
JPS52111080A (en) 1976-03-15 1977-09-17 Kazutoshi Yamazaki Method of obtaining blanks from material of specified length
JPS5553462A (en) * 1978-10-13 1980-04-18 Int Rectifier Corp Mosfet element
JPS5715420A (en) * 1980-06-30 1982-01-26 Nec Home Electronics Ltd Manufacture of semiconductor device
JPS5790763A (en) 1980-11-28 1982-06-05 Fujitsu Ltd Priority process system
JPS5797630A (en) 1980-12-10 1982-06-17 Hitachi Ltd Manufacture of semiconductor device
JPS5845814A (en) * 1981-09-11 1983-03-17 Tatsuji Yamamura Method of manufacturing saw
JPS59113629A (en) * 1982-12-20 1984-06-30 Fujitsu Ltd Semiconductor device
JPS59189625A (en) * 1983-04-13 1984-10-27 Nec Corp Manufacture of semiconductor device
JPS59213140A (en) * 1983-05-18 1984-12-03 Toshiba Corp Manufacture of semiconductor device
JPS59220937A (en) * 1983-05-31 1984-12-12 Toshiba Corp Manufacture of semiconductor device
US4602541A (en) 1984-12-06 1986-07-29 Trumpf Gmbh & Co. Punch press with means for rotating the workpiece and method of using same and tooling therefor
DE3446807A1 (en) * 1984-12-21 1986-07-03 Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt Thin-film solar cell having an n-i-p structure
JPS61230404A (en) 1985-04-03 1986-10-14 Murata Mfg Co Ltd Dielectric coaxial resonator
JPS61234041A (en) * 1985-04-09 1986-10-18 Tdk Corp Semiconductor device and manufacture thereof
JPS61296769A (en) * 1985-06-25 1986-12-27 Yokogawa Electric Corp Production of high withstand voltage mosfet
JPS6223170A (en) * 1985-07-23 1987-01-31 Nec Corp Manufacture of vertical type field-effect transistor for power
JPS6224332A (en) * 1985-07-24 1987-02-02 Usac Electronics Ind Co Ltd Initial diagnosis control system
JPS6243123A (en) * 1985-08-21 1987-02-25 Rohm Co Ltd Formation of ohmic contact in individual semiconductor device
JPS62243332A (en) * 1986-04-15 1987-10-23 Toshiba Corp Processing of semiconductor wafer
US4859629A (en) * 1986-04-18 1989-08-22 M/A-Com, Inc. Method of fabricating a semiconductor beam lead device
JPS62253633A (en) 1986-04-26 1987-11-05 Mazda Motor Corp Electrode structure for corona discharge of surface of pi molded article and production thereof
JP2710249B2 (en) * 1986-06-12 1998-02-10 富士電機株式会社 Switching semiconductor device
SE460147B (en) 1987-03-03 1989-09-11 Asea Stal Ab POWER PLANT WITH FLUIDIZED BATH AND A COOLING DEVICE FOR BEDDING MATERIAL
JPS63253633A (en) * 1987-04-09 1988-10-20 Mitsubishi Electric Corp Manufacture of semiconductor device
US4927784A (en) * 1987-05-01 1990-05-22 Raytheon Company Simultaneous formation of via hole and tube structures for GaAs monolithic microwave integrated circuits
GB8711373D0 (en) * 1987-05-14 1987-06-17 Secr Defence Electroluminescent silicon device
US4751191A (en) * 1987-07-08 1988-06-14 Mobil Solar Energy Corporation Method of fabricating solar cells with silicon nitride coating
JPH01169970A (en) * 1987-12-25 1989-07-05 Hitachi Ltd Semiconductor device
JPH0233367A (en) 1988-07-21 1990-02-02 Daiyu Shoji:Kk Textile or knit having collagen fiber layer of natural leather
US4853345A (en) * 1988-08-22 1989-08-01 Delco Electronics Corporation Process for manufacture of a vertical DMOS transistor
JPH02210860A (en) * 1989-02-09 1990-08-22 Fujitsu Ltd Semiconductor integrated circuit device
JP2854907B2 (en) 1990-01-11 1999-02-10 シチズン時計株式会社 Progressive press die
JP2513055B2 (en) * 1990-02-14 1996-07-03 日本電装株式会社 Method for manufacturing semiconductor device
US5241862A (en) 1990-12-24 1993-09-07 Litton Systems, Inc. Integrated accelerometer with single hardstop geometry
US5333961A (en) 1992-08-05 1994-08-02 Rockwell International Corporation Keyboard with top mountable key cap assemblies and method
JPH07233367A (en) * 1993-12-28 1995-09-05 Toshiba Corp Fluorescent material, slurry fluorescent material and production of fluorescent lump
JP2962396B2 (en) 1994-06-27 1999-10-12 株式会社ユニシアジェックス Inclined hole drilling device
CH688306A5 (en) 1994-09-07 1997-07-31 Eugen Haenggi Method and apparatus for punching Loechernin a flat workpiece.
US5744213A (en) 1995-08-25 1998-04-28 Soltech. Inc. Enclosure panel with herringbone aperture pattern
JPH0973760A (en) 1995-09-07 1997-03-18 Sony Corp Method for blanking plate stock and base plate of tape cassette
US6114193A (en) * 1998-05-05 2000-09-05 Vishay Lite-On Power Semicon Corp. Method for preventing the snap down effect in power rectifier with higher breakdown voltage

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4213818A (en) * 1979-01-04 1980-07-22 Signetics Corporation Selective plasma vapor etching process
US4902641A (en) * 1987-07-31 1990-02-20 Motorola, Inc. Process for making an inverted silicon-on-insulator semiconductor device having a pedestal structure
US4782028A (en) * 1987-08-27 1988-11-01 Santa Barbara Research Center Process methodology for two-sided fabrication of devices on thinned silicon
US4859626A (en) * 1988-06-03 1989-08-22 Texas Instruments Incorporated Method of forming thin epitaxial layers using multistep growth for autodoping control
US4879250A (en) * 1988-09-29 1989-11-07 The Boeing Company Method of making a monolithic interleaved LED/PIN photodetector array
US4985740A (en) * 1989-06-01 1991-01-15 General Electric Company Power field effect devices having low gate sheet resistance and low ohmic contact resistance

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070111480A1 (en) * 2005-11-16 2007-05-17 Denso Corporation Wafer product and processing method therefor
US20080006856A1 (en) * 2006-06-22 2008-01-10 Fuji Electric Device Technology Co., Ltd Semiconductor device with back surface electrode including a stress relaxation film
US7521757B2 (en) * 2006-06-22 2009-04-21 Fuji Electric Device Technology Co., Ltd. Semiconductor device with back surface electrode including a stress relaxation film
US20110039382A1 (en) * 2006-12-07 2011-02-17 Shindengen Electric Manufacturing Co., Ltd. Semiconductor device and method for manufacturing the same
US8343833B2 (en) * 2006-12-07 2013-01-01 Shindengen Electric Manufacturing Co., Ltd. Semiconductor device and method for manufacturing the same
US20130256964A1 (en) * 2012-03-27 2013-10-03 Mitsubishi Electric Corporation Wafer suction method, wafer suction stage, and wafer suction system
US9312160B2 (en) * 2012-03-27 2016-04-12 Mitsubishi Electric Corporation Wafer suction method, wafer suction stage, and wafer suction system

Also Published As

Publication number Publication date
US5242862A (en) 1993-09-07
US20040241930A1 (en) 2004-12-02
US6498366B1 (en) 2002-12-24
US5689130A (en) 1997-11-18
US5663096A (en) 1997-09-02
US7064033B2 (en) 2006-06-20
US5994187A (en) 1999-11-30
US20040237327A1 (en) 2004-12-02
US20030052366A1 (en) 2003-03-20
US6903417B2 (en) 2005-06-07
JPH03236225A (en) 1991-10-22
JP2513055B2 (en) 1996-07-03
US6649478B2 (en) 2003-11-18
US20040036140A1 (en) 2004-02-26
US6949434B2 (en) 2005-09-27

Similar Documents

Publication Publication Date Title
US6903417B2 (en) Power semiconductor device
US5101244A (en) Semiconductor schottky device with pn regions
US5859465A (en) High voltage power schottky with aluminum barrier metal spaced from first diffused ring
US20090035925A1 (en) Gallium Nitride Semiconductor Device
CA1189634A (en) Low-loss and high-speed diodes
US6162665A (en) High voltage transistors and thyristors
US6727128B2 (en) Method of preparing polysilicon FET built on silicon carbide diode substrate
US5218226A (en) Semiconductor device having high breakdown voltage
JPH04127480A (en) High breakdown strength low resistance semiconductor device
US5654226A (en) Wafer bonding for power devices
JP2518963B2 (en) InAs hole element
EP0426252B1 (en) A semiconductor device and method of manufacturing a semiconductor device
JP3313344B2 (en) SiC / Si heterostructure semiconductor switch and method of manufacturing the same
US4246693A (en) Method of fabricating semiconductor device by bonding together silicon substrate and electrode or the like with aluminum
CA1305260C (en) Semiconductor device having array of conductive rods
JPH05275688A (en) Planar type power semiconductor element
US5858855A (en) Semiconductor substrate, process for production thereof, and semiconductor device
US20210066495A1 (en) Power Semiconductor Device and Method
JPH07153928A (en) Semiconductor substrate and its manufacture
US20220139793A1 (en) Power semiconductor devices with improved overcoat adhesion and/or protection
US20220336215A1 (en) Fabrication of wide bandgap devices
JPS63138767A (en) Semiconductor substrate for vertical type semi-conductor device and manufacture thereof
Cohen et al. Si 3 N 4-masked thermally oxidized post-diffused mesa process (SIMTOP)
JPH0770477B2 (en) Method for manufacturing semiconductor device
JPS60117681A (en) Semiconductor device

Legal Events

Date Code Title Description
STCB Information on status: application discontinuation

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