US4135951A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Annealing method to increase minority carrier life-time for neutron transmutation doped semiconductor materials
Assignee: SunEdison Inc
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Filing: 1977-06-13
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Granted: 1979-01-23
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Expires: 1997-06-13
Abstract
Abstract Semiconductor materials which have been doped by neutron transmutation require annealing at high temperatures in order to alleviate radiation damage and to restore electrical resistivity; however, the minority carrier lifetime is reduced significantly through the irradiation and/or the annealing process. A method for increasing the minority carrier lifetime while maintaining the restored electrical resistivity is achieved by cooling the heated annealed materials at a cooling rate less than about 4° C. per minute and preferably less than about 3° C. per minute to ambient temperatures.
Inventors
- 👤 Bobbie B. Stone
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 11:02
CPC Classifications
H; H10; H10P; H10P95/00; H10P95/90; H10P34/00; H10P34/20; Y; Y10; Y10S; Y10S148/00; Y10S148/165
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
81 words
A method for restoring neutron-doped semiconductor material resistivity and increasing the minority carrier lifetime of said material through annealing, comprising: heating the material to an annealing temperature of around 600° C. or more but below the material melting temperature for a period of one-fourth hour to five hours or more; and cooling the heated material from the annealing temperature to ambient temperature of below about 300° C. at a cooling rate of from 1/4° C. to about 4° C. per minute.
Claim 2
Independent Claim
81 words
A method for restoring neutron-doped semiconductor material resistivity and increasing the minority carrier lifetime of said material through annealing, comprising: heating the material to an annealing temperature of around 600° C. or more but below the material melting temperature for a period of one-fourth hour to five hours or more; and cooling the heated material from the annealing temperature to ambient temperature of below about 300° C. at a cooling rate of from 1/4° C. to about 4° C. per minute.
Claim 3
Dependent Claim
12 words
A method according to claim 1 wherein the semiconductor material is silicon.
Claim 4
Dependent Claim
17 words
A method according to claim 2 wherein the annealing temperature is from 600° C. to 1300° C.
Claim 5
Dependent Claim
19 words
A method according to claim 2 wherein the cooling rate is from 1/4° C. to 3° C. per minute.
Claim 6
Dependent Claim
17 words
A method according to claim 2 wherein the annealing temperature is from 600° C. to 900° C.
Claim 7
Dependent Claim
16 words
A method according to claim 2 wherein the annealing period is from one-half to 4 hours.
Claim 8
Independent Claim
77 words
A method for increasing the minority carrier lifetime of neutron transmutation doped semiconductor materials comprising heating the neutron transmutation doped semiconductor materials to an annealing temperature of from 600° to 1300° C. and maintaining the material at the annealing temperature for a period of one-fourth hour to at least 4 hours; and cooling the annealed material from the annealing temperature to ambient temperature at cooling rate of from 1/4° C. to less than 4° C. per minute.
Claim 9
Independent Claim
77 words
A method for increasing the minority carrier lifetime of neutron transmutation doped semiconductor materials comprising heating the neutron transmutation doped semiconductor materials to an annealing temperature of from 600° to 1300° C. and maintaining the material at the annealing temperature for a period of one-fourth hour to at least 4 hours; and cooling the annealed material from the annealing temperature to ambient temperature at cooling rate of from 1/4° C. to less than 4° C. per minute.
Claim 10
Dependent Claim
12 words
A method according to claim 7 wherein the semiconductor material is silicon.
Claim 11
Dependent Claim
17 words
A method according to claim 8 wherein the minority carrier lifetime is increased by 50% or more.
Claim 12
Dependent Claim
19 words
A method according to claim 8 wherein the cooling rate is from 1/2° C. to 3° C. per minute.
References Cited (Backward Citations)
US3914138A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-01-22 | 1982-07-24 | 1983-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-22 | 1986-07-24 | 1987-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-22 | 1990-07-24 | 1991-01-23 | $7700.00 | Window Closed / Lapsed |