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US4151007A
Expired / Lapsed
US
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Hydrogen annealing process for stabilizing metal-oxide-semiconductor structures
Assignee: AT&T Inc
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Filing: 1977-10-11
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Granted: 1979-04-24
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Expires: 1997-10-11
Abstract
Abstract Variations in threshold voltage of Metal-Oxide-Silicon (MOS) structures are attenuated by the inclusion in the fabrication process of a hydrogen anneal step using a temperature range of 650 degrees C≦T≦950 degrees C. This anneal step is designed to be the last step in the fabrication process which is performed at temperatures above 600 degrees C.
Inventors
- 👤 Hyman J. Levinstein
- 👤 Ashok K. Sinha
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:05
CPC Classifications
H; H10; H10P; H10P95/00; H10P95/94; Y; Y10; Y10S; Y10S148/00; Y10S148/003; Y10S148/024; Y10S148/053; Y10S148/128
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
74 words
In a process of fabricating a semiconductor device, the device comprising a semiconductor substrate having a major surface which is at least partially covered by a layer of silicon dioxide, the last fabrication step in the process which is performed at temperatures of 600 degrees C. or greater being the step of heating the semiconductor device in an ambient of hydrogen gas at a temperature in the range of 650 degrees C.≦T≦950 degrees C.
Claim 2
Dependent Claim
74 words
In a process of fabricating a semiconductor device, the device comprising a semiconductor substrate having a major surface which is at least partially covered by a layer of silicon dioxide, the last fabrication step in the process which is performed at temperatures of 600 degrees C. or greater being the step of heating the semiconductor device in an ambient of hydrogen gas at a temperature in the range of 650 degrees C.≦T≦950 degrees C.
Claim 3
Dependent Claim
56 words
The process of claim 1 wherein the semiconductor substrate is n-type with a [111] orientation and the process comprises the step of forming a first conductive layer on the silicon dioxide prior to the heating of the semiconductor device in hydrogen and the temperature range during the hydrogen heating step being 850 degrees C.≦T≦950 degrees C.
Claim 4
Dependent Claim
46 words
The process of claim 2 further comprising the step of forming a second conductive layer over the major surface of the semiconductor device, said second conductive layer being formed at a temperature below 600 degrees C. and the first conductive layer being phosphorus doped polycrystalline silicon.
Claim 5
Dependent Claim
12 words
The process of claim 3 wherein the second conductive layer is aluminum.
Claim 6
Dependent Claim
34 words
The process of claim 2 wherein the first conductive layer is boron doped polycrystalline silicon and the temperature range for the heating of the semiconductor device in hydrogen is 650 degrees C.≦T≦750 degrees C.
Claim 7
Dependent Claim
12 words
The process of claim 5 wherein the second conductive layer is aluminum.
Claim 8
Dependent Claim
51 words
The process of claim 1 wherein the semiconductor substrate is p-type silicon with a [100]orientation and a first conductive layer is selectively formed on the silicon dioxide prior to the heating of the semiconductor device in hydrogen and the temperature range of the heating step is 850 degrees C.≦T≦950 degrees C.
Claim 9
Dependent Claim
36 words
The process of claim 1 further comprising the step of forming a second conductive layer on the semiconductor device at a temperature below 600 degrees C. and the first conductive layer being phosphorus doped polycrystalline silicon.
Claim 10
Dependent Claim
18 words
The process of claim 8 wherein the second conductive layer is aluminum and is deposited by magnetron sputtering.
Claim 11
Dependent Claim
86 words
In a process of fabricating a semiconductor device, the device comprising a semiconductor substrate having a major surface which is at least partially covered by a layer of silicon dioxide, the last fabrication step in the process which is performed at temperatures of 600 degrees C. or greater being the step of heating the semiconductor device in an ambient of hydrogen gas at a temperature in the range of 650 degrees C.≦T≦950 degrees C., the hydrogen heating step being performed prior to metallization of the device.
Claim 12
Dependent Claim
86 words
In a process of fabricating a semiconductor device, the device comprising a semiconductor substrate having a major surface which is at least partially covered by a layer of silicon dioxide, the last fabrication step in the process which is performed at temperatures of 600 degrees C. or greater being the step of heating the semiconductor device in an ambient of hydrogen gas at a temperature in the range of 650 degrees C.≦T≦950 degrees C., the hydrogen heating step being performed prior to metallization of the device.
Claim 13
Dependent Claim
68 words
The process of fabricating an MOS silicon device which is characterized in that the last step in the processing which involves heating the device to a temperature above 600 degrees C. is a step in which the device is heated to a temperature of between 650 degrees C. and 950 degrees C. for approximately a half hour or greater in an ambient which consists essentially of hydrogen gas.
Claim 14
Dependent Claim
68 words
The process of fabricating an MOS silicon device which is characterized in that the last step in the processing which involves heating the device to a temperature above 600 degrees C. is a step in which the device is heated to a temperature of between 650 degrees C. and 950 degrees C. for approximately a half hour or greater in an ambient which consists essentially of hydrogen gas.
References Cited (Backward Citations)
US3852120A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-04-23 | 1982-10-23 | 1983-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-23 | 1986-10-23 | 1987-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-23 | 1990-10-23 | 1991-04-24 | $7700.00 | Window Closed / Lapsed |