US5323022A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Platinum ohmic contact to p-type silicon carbide
Assignee: North Carolina State University
•
Filing: 1992-09-10
•
Granted: 1994-06-21
•
Expires: 2012-09-10
Abstract
Abstract A method and resulting ohmic contact structure between a high work function metal and a wide bandgap semiconductor for which the work function of the metal would ordinarily be insufficient to form an ohmic contact between the metal and the semiconductor. The structure can withstand annealing while retaining ohmic characteristics. The ohmic contact structure comprises a portion of single crystal wide bandgap semiconductor material; a contact formed of a high work function metal on the semiconductor portion; and a layer of doped p-type semiconductor material between the single crystal portion and the metal contact. The doped layer has a sufficient concentration of p-type dopant to provide ohmic behavior between the metal and the semiconductor material.
Inventors
- 👤 Robert C. Glass
- 👤 John W. Palmour
- 👤 Robert F. Davis
- 👤 Lisa S. Porter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:37
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/80; H10D62/83; H10D62/832; H10D62/8325; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D64/0115; H10D64/60; H10D64/62; Y; Y10; Y10S; Y10S148/00; Y10S148/148
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
89 words
An ohmic contact structure between platinum and silicon carbide, and that can withstand annealing while retaining ohmic characteristics, said ohmic contact structure comprising: a portion of single crystal p-type silicon carbide; a platinum contact on said single crystal silicon carbide portion; and a layer of doped p-type silicon carbide having a depletion region and being between said single crystal silicon carbide portion and said platinum contact, said doped layer having a sufficient concentration of p-type dopant to provide ohmic behavior between said silicon carbide portion and said platinum contact.
Claim 2
Dependent Claim
89 words
An ohmic contact structure between platinum and silicon carbide, and that can withstand annealing while retaining ohmic characteristics, said ohmic contact structure comprising: a portion of single crystal p-type silicon carbide; a platinum contact on said single crystal silicon carbide portion; and a layer of doped p-type silicon carbide having a depletion region and being between said single crystal silicon carbide portion and said platinum contact, said doped layer having a sufficient concentration of p-type dopant to provide ohmic behavior between said silicon carbide portion and said platinum contact.
Claim 3
Dependent Claim
51 words
An ohmic contact structure according to claim 1 wherein said doped layer has a sufficient concentration of p-type dopant to reduce the width of the depletion region formed by said metal contact and said semiconductor enough to allow carrier tunneling transport across the interface between said metal contact and said semiconductor.
Claim 4
Dependent Claim
22 words
An ohmic contact structure according to claim 1 wherein said doped layer comprises an ion implanted region in said single crystal portion.
Claim 5
Dependent Claim
16 words
An ohmic contact structure according to claim 1 wherein said doped layer comprises an epitaxial layer.
Claim 6
Dependent Claim
20 words
An ohmic contact structure according to claim 1 wherein said single crystal portion of silicon carbide comprises an epitaxial layer.
Claim 7
Dependent Claim
17 words
An ohmic contact structure according to claim 1 wherein said doped p-type layer is doped with aluminum.
Claim 8
Dependent Claim
17 words
An ohmic contact structure according to claim 1 wherein said doped p-type layer is doped with boron.
Claim 9
Dependent Claim
25 words
An ohmic contact structure according to claim 1 wherein said doped p-type layer has a carrier concentration of at least 10 17 cm -3 .
Claim 10
Dependent Claim
25 words
An ohmic contact structure according to claim 1 wherein said doped p-type layer has a carrier concentration of at least 5×10 18 cm -3 .
Claim 11
Dependent Claim
25 words
An ohmic contact structure according to claim 1 wherein said doped p-type layer has a carrier concentration of at least 10 19 cm -3 .
Claim 12
Dependent Claim
23 words
An ohmic contact structure according to claim 1 and further comprising a platinum-silicide composition between said doped p-type layer and said platinum contact.
Claim 13
Dependent Claim
20 words
An ohmic contact structure according to claim 1 wherein said doped p-type layer has a thickness of about 100 angstroms.
Claim 14
Dependent Claim
16 words
An ohmic contact structure according to claim 1 wherein said silicon carbide comprises a 6H polytype.
Claim 15
Dependent Claim
28 words
An ohmic contact structure according to claim 1 wherein said silicon carbide is selected from the group consisting of the 3C, 2H, 4H, 6H, 8H and 15R polytypes.
References Cited (Backward Citations)
US3714520A
Cited
US4263605A
Cited
US4801984A
Cited
US4513309A
Cited
US4583110A
Cited
US4772934A
Cited
US5098859A
Cited
US4907040A
Cited
US5087576A
Cited
US5012320A
Cited
US5006914A
Cited
US5027168A
Cited
JPH02196421A
Cited
US5210431A
Cited
US4966862A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-06-20 | 1997-12-20 | 1998-06-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-06-20 | 2001-12-20 | 2002-06-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-06-20 | 2005-12-20 | 2006-06-21 | $7700.00 | Window Closed / Lapsed |