US3896479A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reduced stresses in iii-v semiconductor devices
Assignee: AT&T Inc
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Filing: 1974-03-04
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Granted: 1975-07-22
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Expires: 1994-03-04
Abstract
Abstract Substrate tensile stresses resulting from the combination of an electroplated gold or silver heat sink with a metal contact on III-V semiconductor devices, such as GaAs IMPATT diodes, may be substantially compensated by interposing a layer of tungsten under compressive stress between the contact layer and the heat sink. Since gold or silver is not easily plated on tungsten, a thin layer of platinum is deposited over the tungsten layer prior to forming the heat sink.
Inventors
- 👤 Lorenzo James Vincent Di
- 👤 George Arthur Rozgonyi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:47
CPC Classifications
H; H10; H10W; H10W72/00; H10W72/30; H10D; H10D8/00; H10D8/40; H10W40/00; H10W40/10; H10W72/071; H10W72/073; H10W72/07331; H10W72/07336; H10W72/50; H10W72/531; H10W72/5363; Y; Y10; Y10S; Y10S148/00; Y10S148/02
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
120 words
A method of fabricating a substantially stress-compensated contact on a III-V semiconductor device, the method comprising: a. forming a metal layer on a III-V semiconductor surface; and b. forming an electroplated heat sink layer of gold or silver over the metal layer, characterized in that prior to forming the heat sink layer, a multilayer structure is formed on the layer, the multilayer structure comprising: a. a tungsten layer, under compressive stress, formed and deposited on the metal layer by means of rf sputtering, and compensating sufficiently for the stress of the metal layer so that the resultant radius of curvature of the multilayer structure is greater than 5 meters; and b. a thin platinum layer formed on the tungsten layer.
Claim 2
Independent Claim
120 words
A method of fabricating a substantially stress-compensated contact on a III-V semiconductor device, the method comprising: a. forming a metal layer on a III-V semiconductor surface; and b. forming an electroplated heat sink layer of gold or silver over the metal layer, characterized in that prior to forming the heat sink layer, a multilayer structure is formed on the layer, the multilayer structure comprising: a. a tungsten layer, under compressive stress, formed and deposited on the metal layer by means of rf sputtering, and compensating sufficiently for the stress of the metal layer so that the resultant radius of curvature of the multilayer structure is greater than 5 meters; and b. a thin platinum layer formed on the tungsten layer.
Claim 3
Dependent Claim
17 words
The method of claim 1 in which the metal layer is a Schottky barrier contact of platinum.
Claim 4
Dependent Claim
14 words
The method of claim 1 in which the metal layer is an ohmic contact.
Claim 5
Dependent Claim
13 words
The method of claim 1 in which the semiconductor surface is gallium arsenide.
Claim 6
Dependent Claim
39 words
The method of claim 1 in which the tungsten layer ranges from about 0.1 micrometers to about 0.7 micrometers in thickness and in which the thin platinum layer ranges from about 0.05 micrometers to about 0.2 micrometers in thickness.
Claim 7
Dependent Claim
99 words
A III-V SEMICONDUCTOR DEVICE COMPRISING: A. A METAL LAYER ON A SEMICONDUCTOR SURFACE, AND B. A HEAT SINK LAYER OF GOLD OR SILVER ON THE METAL LAYER, CHARACTERIZED IN THAT A MULTILAYER STRUCTURE IS INTERPOSED BETWEEN THE METAL LAYER AND THE HEAT SINK LAYER, THE MULTILAYER STRUCTURE COMPRISING: A. A TUNGSTEN LAYER, UNDER COMPRESIVE STRESS, FORMED AND DEPOSITED ON THE METAL LAYER BY MEANS OF RF SPUTTERING AND COMPENSATING SUFFICIENTLY FOR THE STRESS OF THEMETAL LAYER SO THAT THE RESULTANT RADIUS OF CURVATURE IS GREATER THAN 5 METERS, AND B. A THIN PLATINUM LAYER FORMED ON THE TUNGSTEN LAYER.
Claim 8
Dependent Claim
99 words
A III-V SEMICONDUCTOR DEVICE COMPRISING: A. A METAL LAYER ON A SEMICONDUCTOR SURFACE, AND B. A HEAT SINK LAYER OF GOLD OR SILVER ON THE METAL LAYER, CHARACTERIZED IN THAT A MULTILAYER STRUCTURE IS INTERPOSED BETWEEN THE METAL LAYER AND THE HEAT SINK LAYER, THE MULTILAYER STRUCTURE COMPRISING: A. A TUNGSTEN LAYER, UNDER COMPRESIVE STRESS, FORMED AND DEPOSITED ON THE METAL LAYER BY MEANS OF RF SPUTTERING AND COMPENSATING SUFFICIENTLY FOR THE STRESS OF THEMETAL LAYER SO THAT THE RESULTANT RADIUS OF CURVATURE IS GREATER THAN 5 METERS, AND B. A THIN PLATINUM LAYER FORMED ON THE TUNGSTEN LAYER.
Claim 9
Dependent Claim
17 words
The device of claim 6 in which the metal layer is a Schottky barrier contact of platinum.
Claim 10
Dependent Claim
15 words
The device of claim 7 in which the device is a gallium arsenide IMPATT diode.
Claim 11
Dependent Claim
14 words
The device of claim 6 in which the metal layer is an ohmic contact.
Claim 12
Dependent Claim
38 words
The device of claim 6 in which the tungsten layer ranges from about 0.1 micrometers to 0.7 micrometers in thickness and in which the thin platinum layer ranges from about 0.05 micrometers to about 0.2 micrometers in thickness.
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) | 1978-07-21 | 1979-01-20 | 1979-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-21 | 1983-01-20 | 1983-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-21 | 1987-01-20 | 1987-07-22 | $7700.00 | Window Closed / Lapsed |