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US4684413A
Expired / Lapsed
US
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Method for increasing the switching speed of a semiconductor device by neutron irradiation
Assignee: Fairchild Semiconductor Corp
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Filing: 1985-10-07
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Granted: 1987-08-04
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Expires: 2005-10-07
Abstract
Abstract A method for decreasing the turnoff time in a crystalline semiconductor region within a semiconductor device comprises initially providing a semiconductor region having a predetermined density of pinning centers. The semiconductor region is then irradiated so as to yield crystal damage that is equivalent to or greater than that which would be produced by irradiating with 1 MeV neutrons at a fluence greater than approximately 10 13 cm -2 . The region is then annealed at a temperature of approximately 350° to 450° C. for approximately 15 minutes to one hour so as to yield a density of stable recombination centers correlating with the pinning centers that provides a stable minority carrier lifetime within the semiconductor region.
Inventors
- 👤 Alvin M. Goodman
- 👤 Lawrence A. Goodman
- 👤 John P. Russell
- 👤 Paul H. Robinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:12
CPC Classifications
H; H10; H10D; H10D12/00; H10D12/411; H10D12/441; H10D62/00; H10D62/50; H10D62/53; H10P; H10P34/00; H10P34/40; Y; Y10; Y10S; Y10S438/00; Y10S438/904
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
105 words
A method for decreasing turnoff time in a crystalline semiconductor region within a semiconductor device comprising the steps of: providing pinning centers, at a density greater than 0.1 ppma, in the semiconductor region; irradiating the region so as to yield crystal damage that is equivalent to or greater than irradiating with 1 MeV neutrons at a fluence greater than approximately 10 13 cm -2 ; and annealing the region at approximately 350°-450° C. for approximately 15 minutes to 1 hour so as to yield a density of stable recombination centers correlating with the pinning centers that provide a stable minority carrier lifetime within the region.
Claim 2
Independent Claim
105 words
A method for decreasing turnoff time in a crystalline semiconductor region within a semiconductor device comprising the steps of: providing pinning centers, at a density greater than 0.1 ppma, in the semiconductor region; irradiating the region so as to yield crystal damage that is equivalent to or greater than irradiating with 1 MeV neutrons at a fluence greater than approximately 10 13 cm -2 ; and annealing the region at approximately 350°-450° C. for approximately 15 minutes to 1 hour so as to yield a density of stable recombination centers correlating with the pinning centers that provide a stable minority carrier lifetime within the region.
Claim 3
Dependent Claim
17 words
A method in accordance with claim 1 wherein the semiconductor region is silicon of P type conductivity.
Claim 4
Dependent Claim
17 words
A method in accordance with claim 1 wherein the semiconductor region is silicon of N type conductivity.
Claim 5
Dependent Claim
18 words
A method in accordance with claim 1 further comprising an oxide at the surface of the semiconductor device.
Claim 6
Dependent Claim
24 words
A method in accordance with claim 1 wherein said pinning centers are provided by introducing crystalline defects during the formation of said semiconductor region.
Claim 7
Dependent Claim
25 words
A method in accordance with claim 1 wherein said pinning centers are provided by introducing crystalline defects subsequent to the formation of said semiconductor region.
Claim 8
Dependent Claim
24 words
A method in accordance with claim 1 wherein said pinning centers are provided by epitaxially forming said semiconductor region in the presence of oxygen.
Claim 9
Dependent Claim
27 words
A method in accordance with claim 1 wherein said pinning centers are provided by oxidizing said semiconductor region and subjecting the oxidized region to a diffusion cycle.
Claim 10
Dependent Claim
29 words
A method in accordance with claim 1 wherein said pinning centers are provided by ion implanting oxygen into said semiconductor region and diffusing the oxygen within the semiconductor region.
Claim 11
Dependent Claim
19 words
A method in accordance with claim 1 wherein said semiconductor region is silicon produced by a float zone process.
Claim 12
Dependent Claim
17 words
A method in accordance with claim 1 wherein said predetermined density is approximately 0.5 to 1.5 ppma.
References Cited (Backward Citations)
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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) | 1990-08-03 | 1991-02-02 | 1991-08-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-08-03 | 1995-02-02 | 1995-08-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-08-03 | 1999-02-02 | 1999-08-04 | $7700.00 | Window Closed / Lapsed |