Patent US4849802A successfully refreshed from Google Patents.
US4849802A
Expired / Lapsed
US
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Thermally stable low resistance contact
Assignee: International Business Machines Corp
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Filing: 1988-08-16
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Granted: 1989-07-18
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Expires: 2008-08-16
Abstract
Abstract In a semiconductor device, a contact with low resistance to a III-V compound semiconductor substrate was fabricated using refractory materials and small amounts of indium as the contact material. The contact material was formed by depositing Mo, Ge and W with small amounts of In onto doped GaAs wafers. The contact resistance less than 1.0 ohm millimeter was obtained after annealing at 800° C. and the resistance did not increase after subsequent prolonged annealing at 400° C.
Inventors
- 👤 Thomas N. Jackson
- 👤 Masanori Murakami
- 👤 William H. Price
- 👤 Sandip Tiwari
- 👤 Jerry M. Woodall
- 👤 Steven L. Wright
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:16
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/60; H10D64/62; H10D62/00; H10D62/80; H10D62/85
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
76 words
In a III-V compound semiconductor device, a contact to a layer of said semiconductor comprising: at least one conductive refractory material deposited as a layer along a surface of said semiconductor layer; and wherein atoms of indium are diffused along an interface between said refractory layer and said semiconductor layer to form a non-alloyed contact, the amount of said indium being equal to a layer of indium having a thickness in the range of 5-100 angstroms.
Claim 2
Dependent Claim
76 words
In a III-V compound semiconductor device, a contact to a layer of said semiconductor comprising: at least one conductive refractory material deposited as a layer along a surface of said semiconductor layer; and wherein atoms of indium are diffused along an interface between said refractory layer and said semiconductor layer to form a non-alloyed contact, the amount of said indium being equal to a layer of indium having a thickness in the range of 5-100 angstroms.
Claim 3
Dependent Claim
11 words
A contact according to claim 1 wherein said semiconductor is gallium-arsenide.
Claim 4
Dependent Claim
11 words
A contact according to claim 1 wherein said semiconductor is gallium-aluminum-arsenide.
Claim 5
Dependent Claim
11 words
A contact according to claim 1 wherein said semiconductor is gallium-indium-arsenide.
Claim 6
Dependent Claim
32 words
A ohmic contact according to claim 1 further comprising a second layer of said refractory material, one of said refractory layers being molybdenum, and the second of said refractory layers being tungsten.
Claim 7
Dependent Claim
19 words
An ohmic contact according to claim 5 further comprising a layer of dopant material, said dopant layer being germanium.
Claim 8
Dependent Claim
90 words
In a III-V compound semiconductor device, a contact to a layer of said semiconductor comprising: at least one conductive refractory material deposited as a layer along a surface of said semiconductor layer; at least one dopant material appropriate for the conductivity type of said semiconductor; and wherein atoms of indium are diffused along an interface between said refractory layer and said semiconductor layer to form a uniform thermally-stable contact, the amount of said indium being equal to a layer of indium having a thickness in the range of 5-100 angstroms.
Claim 9
Dependent Claim
90 words
In a III-V compound semiconductor device, a contact to a layer of said semiconductor comprising: at least one conductive refractory material deposited as a layer along a surface of said semiconductor layer; at least one dopant material appropriate for the conductivity type of said semiconductor; and wherein atoms of indium are diffused along an interface between said refractory layer and said semiconductor layer to form a uniform thermally-stable contact, the amount of said indium being equal to a layer of indium having a thickness in the range of 5-100 angstroms.
Claim 10
Dependent Claim
11 words
A contact according to claim 7 wherein said semiconductor is gallium-arsenide.
Claim 11
Dependent Claim
11 words
A contact according to claim 7 wherein said semiconductor is gallium-aluminum-arsenide.
Claim 12
Dependent Claim
11 words
A contact according to claim 7 wherein said semiconductor is gallium-indium-arsenide.
Claim 13
Dependent Claim
32 words
An ohmic contact according to claim 7 further comprising a second layer of said refractory material, one of said refractory layers being molybdenum, and the second of said refractory layers being tungsten.
Claim 14
Dependent Claim
17 words
A contact according to claim 7 wherein said semiconductor is n-type and said dopant material is germanium.
Claim 15
Dependent Claim
15 words
A contact according to claim 7 wherein refractory material comprises layers of molybdenum and tungsten.
Claim 16
Dependent Claim
86 words
In a III-V compound semiconductor device, a contact to a layer of said semiconductor made by the process of: depositing a layer of indium on a substrate of said semiconductor to a depth in the range of 5-100 angstroms; depositing a layer of refractory material composed of at least one conductive refractory material upon said layer of indium resulting in a layered structure; and annealing said layered structure at a temperature sufficiently high to induce diffusion of indium atoms from said indium layer into said substrate.
Claim 17
Dependent Claim
86 words
In a III-V compound semiconductor device, a contact to a layer of said semiconductor made by the process of: depositing a layer of indium on a substrate of said semiconductor to a depth in the range of 5-100 angstroms; depositing a layer of refractory material composed of at least one conductive refractory material upon said layer of indium resulting in a layered structure; and annealing said layered structure at a temperature sufficiently high to induce diffusion of indium atoms from said indium layer into said substrate.
Claim 18
Dependent Claim
31 words
A contact according to claim 14 wherein the process further comprises a step of depositing a layer of dopant on said substrate prior to said step of depositing said indium layer.
Claim 19
Dependent Claim
35 words
A contact according to claim 15 wherein said substrate is GaAs, said dopant layer is a layer of germanium having a thickness of approximately 100 angstroms, and said annealing temperature is approximately 800 degrees centigrade.
Claim 20
Dependent Claim
122 words
In a III-V compound semiconductor device, a contact to a semiconductor layer of said device comprising: a refractory layer of conductive refractory material; a dopant layer of dopant material appropriate for the conductivity type of said semiconductor, said dopant layer being disposed between said refractory layer and said semiconductor layer; and atoms of indium diffused into said refractory layer at an interface between said refractory layer and said dopant layer, said atoms of indium being further diffused through said dopant layer and along an interface between said dopant layer and said semiconductor layer to form a uniform thermally-stable contact, the amount of said indium being equal to a layer of indium having a layer of thickness in the rang of 5-100 angstroms.
Claim 21
Dependent Claim
122 words
In a III-V compound semiconductor device, a contact to a semiconductor layer of said device comprising: a refractory layer of conductive refractory material; a dopant layer of dopant material appropriate for the conductivity type of said semiconductor, said dopant layer being disposed between said refractory layer and said semiconductor layer; and atoms of indium diffused into said refractory layer at an interface between said refractory layer and said dopant layer, said atoms of indium being further diffused through said dopant layer and along an interface between said dopant layer and said semiconductor layer to form a uniform thermally-stable contact, the amount of said indium being equal to a layer of indium having a layer of thickness in the rang of 5-100 angstroms.
Claim 22
Dependent Claim
42 words
A contact according to claim 17 wherein said refractory layer is formed of molybdenum, said dopant layer is formed of germanium, and said semiconductor layer is formed of gallium arsenide, and wherein the thickness of said dopant layer is approximately 100 angstroms..
Claim 23
Dependent Claim
25 words
A contact according to claim 18 further comprising a second refractory layer disposed on a side of said first-mentioned refractory layer opposite said dopant layer.
Claim 24
Dependent Claim
15 words
A contact according to claim 19 wherein said second refractory layer is formed of tungsten.
Claim 25
Dependent Claim
39 words
A contact according to claim 17 further comprising a second refractory layer disposed on a side of said first-mentioned refractory layer opposite said dopant layer, said first refractory layer being of a different material than said second refractory layer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-07-17 | 1993-01-16 | 1993-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-17 | 1997-01-16 | 1997-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-17 | 2001-01-16 | 2001-07-18 | $7700.00 | Window Closed / Lapsed |