US4301188A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing contact to GaAs active region
Assignee: AT&T Inc
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Filing: 1979-10-01
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Granted: 1981-11-17
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Expires: 1999-10-01
Abstract
Abstract The stability of semiconductor devices such as gallium arsenide field effect transistors are significantly improved by controlling the process leading to the production of the drain contact. The process requires that the annealing of metals used to form the contact to gallium arsenide is done under conditions which prevent the excessive formation of metal dendrites penetrating into the gallium arsenide active region.
Inventors
- 👤 William C. Niehaus
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:36
CPC Classifications
H; H10; H10D; H10D30/00; H10D30/01; H10D30/061; H10D30/0612; H10D64/00; H10D64/01; H10D64/011; H10D64/0116; H10D64/20; H10D64/23; H10D64/251; H10D64/256; Y; Y10; Y10S; Y10S148/00; Y10S148/02; Y10S148/088
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
92 words
A process for producing an electrical contact to a GaAs active region of a transistor semiconductor device comprising the steps of depositing a metal body onto a semiconductor which is ultimately formed into a pad, said semiconductor pad being in intimate contact with said GaAs active region, and annealing said metal composition at an elevated temperature CHARACTERIZED IN THAT said pad is up to 0.5 μm thick and said temperature and the composition of said metal body is controlled to prevent formation of metallic dendrites that extend into said GaAs active region.
Claim 2
Dependent Claim
92 words
A process for producing an electrical contact to a GaAs active region of a transistor semiconductor device comprising the steps of depositing a metal body onto a semiconductor which is ultimately formed into a pad, said semiconductor pad being in intimate contact with said GaAs active region, and annealing said metal composition at an elevated temperature CHARACTERIZED IN THAT said pad is up to 0.5 μm thick and said temperature and the composition of said metal body is controlled to prevent formation of metallic dendrites that extend into said GaAs active region.
Claim 3
Dependent Claim
19 words
The process of claim 1 wherein said temperature is in the range 400 degrees C. to 450 degrees C.
Claim 4
Dependent Claim
19 words
The process of claim 2 wherein said temperature is in the range 400 degrees C. to 420 degrees C.
Claim 5
Dependent Claim
14 words
The process of claim 1 wherein said metal body comprises three sequentially deposited layers.
Claim 6
Dependent Claim
102 words
A process for producing an electrical contact to a GaAs active region of a transistor semiconductor device comprising the steps of depositing a metal body onto a semiconductor which is ultimately formed into a pad, said semiconductor pad being in intimate contact with said GaAs active region, and annealing said metal composition at an elevated temperature CHARACTERIZED IN THAT said temperature and the composition of said metal body is controlled to prevent formation of metallic dendrites that extend into said GaAs active region wherein said metallic body comprises a layer of Au/Ge composition, a layer of Ag, and a layer of Au.
Claim 7
Dependent Claim
102 words
A process for producing an electrical contact to a GaAs active region of a transistor semiconductor device comprising the steps of depositing a metal body onto a semiconductor which is ultimately formed into a pad, said semiconductor pad being in intimate contact with said GaAs active region, and annealing said metal composition at an elevated temperature CHARACTERIZED IN THAT said temperature and the composition of said metal body is controlled to prevent formation of metallic dendrites that extend into said GaAs active region wherein said metallic body comprises a layer of Au/Ge composition, a layer of Ag, and a layer of Au.
Claim 8
Dependent Claim
102 words
A process for producing an electrical contact to a GaAs active region of a transistor semiconductor device comprising the steps of depositing a metal body onto a semiconductor which is ultimately formed into a pad, said semiconductor pad being in intimate contact with said GaAs active region, and annealing said metal composition at an elevated temperature CHARACTERIZED IN THAT said temperature and the composition of said metal body is controlled to prevent formation of metallic dendrites that extend into said GaAs active region wherein said metallic body comprises a layer of Au, a layer of Ag, and a layer of Au/Ge composition.
Claim 9
Dependent Claim
102 words
A process for producing an electrical contact to a GaAs active region of a transistor semiconductor device comprising the steps of depositing a metal body onto a semiconductor which is ultimately formed into a pad, said semiconductor pad being in intimate contact with said GaAs active region, and annealing said metal composition at an elevated temperature CHARACTERIZED IN THAT said temperature and the composition of said metal body is controlled to prevent formation of metallic dendrites that extend into said GaAs active region wherein said metallic body comprises a layer of Au, a layer of Ag, and a layer of Au/Ge composition.
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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) | 1984-11-16 | 1985-05-18 | 1985-11-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-16 | 1989-05-18 | 1989-11-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-16 | 1993-05-18 | 1993-11-17 | $7700.00 | Window Closed / Lapsed |