Patent US4889831A successfully refreshed from Google Patents.
US4889831A
Expired / Lapsed
US
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Method of forming a high temperature stable ohmic contact to a III-V substrate
Assignee: Fujitsu Ltd
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Filing: 1987-11-30
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Granted: 1989-12-26
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Expires: 2007-11-30
Abstract
Abstract An electrode structure of an electrode of a refractory metal or a silicide thereof on a layer of In x Ga 1-x As (0<x<1) on a substrate of a III-V compound semiconductor is ohmic and is stable even at a high temperature, for example, 900° C. This high temperature stable ohmic electrode structure allows ion implantation into the substrate with the electrode as a mask followed by annealing to form a doped region in alignment with the edge of the electrode.
Inventors
- 👤 Kazuaki Ishii
- 👤 Toshiro Futatsugi
- 👤 Toshio Oshima
- 👤 Toshio Fujii
- 👤 Naoki Yokoyama
- 👤 Akihiro Shibatomi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:56
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/051; H10D10/00; H10D10/01; H10D10/021; H10D10/80; H10D10/821; H10D30/80; H10D30/83; H10D64/00; H10D64/01; H10D64/011; H10D64/0116; H10D64/60; H10D64/62; H10D62/00; H10D62/80; H10D62/85; Y; Y10; Y10S; Y10S148/00; Y10S148/01; Y10S148/065
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
184 words
A process for manufacturing a semiconductor device, comprising the steps of: preparing a substrate of a III-V compound semiconductor having a type of conductivity; forming a layer of In x Ga 1-x As on the substrate, wherein the layer has x greater than 0 and less than 1, wherein said layer has a type of conductivity the same as the type of conductivity of the substrate, and wherein the layer forms an ohmic contact with the substrate; forming an electrode of a refractory metal or a silicide thereof on the In x Ga 1-x As layer, wherein the electrode has an edge and forms an ohmic contact with the In x Ga 1-x As layer; patterning the In x Ga 1-x As layer in alignment with the edge of the electrode with the electrode as a mask; locally implanting an ion into a region of the substrate with the electrode as a mask, so as to have the ion-implanted region of the substrate be made in alignment with the edge of the electrode; and heat annealing to activate the ion-implanted region of the substrate.
Claim 2
Dependent Claim
184 words
A process for manufacturing a semiconductor device, comprising the steps of: preparing a substrate of a III-V compound semiconductor having a type of conductivity; forming a layer of In x Ga 1-x As on the substrate, wherein the layer has x greater than 0 and less than 1, wherein said layer has a type of conductivity the same as the type of conductivity of the substrate, and wherein the layer forms an ohmic contact with the substrate; forming an electrode of a refractory metal or a silicide thereof on the In x Ga 1-x As layer, wherein the electrode has an edge and forms an ohmic contact with the In x Ga 1-x As layer; patterning the In x Ga 1-x As layer in alignment with the edge of the electrode with the electrode as a mask; locally implanting an ion into a region of the substrate with the electrode as a mask, so as to have the ion-implanted region of the substrate be made in alignment with the edge of the electrode; and heat annealing to activate the ion-implanted region of the substrate.
Claim 3
Dependent Claim
31 words
A process according to claim 1, further comprising a step of forming a buffer layer between the substrate and the In x Ga 1-x As layer to match the lattices therebetween.
Claim 4
Dependent Claim
25 words
A process according to claim 1, wherein the III-V compound semiconductor is selected from the group consisting of GaAs, InP, AlGaAs, InGaAs, InAlP and InAlAs.
Claim 5
Dependent Claim
22 words
A process according to claim 1, wherein x of the In x Ga 1-x As is a value between 0.5 and 1.0.
Claim 6
Dependent Claim
17 words
A process according to claim 4, wherein x of the In x Ga 1-x As is 0.53.
Claim 7
Dependent Claim
20 words
A process according to claim 1, wherein the refractory metal is selected from the group of tungsten, molybdenum and tantalum.
Claim 8
Dependent Claim
25 words
A process according to claim 1, wherein the In x Ga 1-x As layer is side etched slightly inward from the edge of the electrode.
Claim 9
Dependent Claim
33 words
A process according to claim 1, further comprising a step of forming an insulating film on the side walls of the electrode and the In x Ga 1-x As layer after patterning thereof.
Claim 10
Dependent Claim
23 words
A process according to claim 1, wherein the heat annealing step is performed at a temperature equal to or more than 650° C.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-12-25 | 1993-06-26 | 1993-12-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-12-25 | 1997-06-26 | 1997-12-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-12-25 | 2001-06-26 | 2001-12-26 | $7700.00 | Window Closed / Lapsed |