Patent US4998158A successfully refreshed from Google Patents.
US4998158A
Expired / Lapsed
US
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Hypoeutectic ohmic contact to N-type gallium arsenide with diffusion barrier
Assignee: NXP USA Inc
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Filing: 1987-06-01
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Granted: 1991-03-05
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Expires: 2007-06-01
Abstract
Abstract A hypoeutectic ohmic contact to gallium arsenide comprising a refractory metal layer is provided which reduces the outdiffusion of gallium and arsenic which would otherwise be seen as impurities at the outer surface of the ohmic contact.
Inventors
- 👤 Karl J. Johnson
- 👤 Charles E. Weitzel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:30
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/80; H10D62/85; H10D64/00; H10D64/60; H10D64/62
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
144 words
An ohmic contact for a portion of a GaAs surface of a semiconductor device having at least one GaAs surface, said ohmic contact comprising: a layer of nickel provided over said portion of said GaAs surface; a layer of germanium provided over said nickel layer; a first gold layer provided over said germanium layer; a refractory metal layer provided over said first gold layer; and a second gold layer provided over said refractory metal layer, wherein said germanium layer and said first gold layer form a hypoeutectic ratio and a portion of said refractory metal layer is diffused into said first and second gold layers to form a stable refractory metal layer which acts as a barrier to reduce migration of gallium or arsenic from said gallium arsenide surface to said second gold layer; and wherein said hypoeutectic ratio is Au 0.973 Ge 0.027.
Claim 2
Dependent Claim
144 words
An ohmic contact for a portion of a GaAs surface of a semiconductor device having at least one GaAs surface, said ohmic contact comprising: a layer of nickel provided over said portion of said GaAs surface; a layer of germanium provided over said nickel layer; a first gold layer provided over said germanium layer; a refractory metal layer provided over said first gold layer; and a second gold layer provided over said refractory metal layer, wherein said germanium layer and said first gold layer form a hypoeutectic ratio and a portion of said refractory metal layer is diffused into said first and second gold layers to form a stable refractory metal layer which acts as a barrier to reduce migration of gallium or arsenic from said gallium arsenide surface to said second gold layer; and wherein said hypoeutectic ratio is Au 0.973 Ge 0.027.
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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) | 1994-03-04 | 1994-09-03 | 1995-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-03-04 | 1998-09-03 | 1999-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-03-04 | 2002-09-03 | 2003-03-05 | $7700.00 | Window Closed / Lapsed |