US4634473A
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Method for fabricating a radiation hardened oxide having structural damage
Assignee: Fairchild Semiconductor Corp
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Filing: 1985-09-09
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Granted: 1987-01-06
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Expires: 2005-09-09
Abstract
Abstract A method for making a partially radiation hardened oxide adjacent an edge comprises forming an oxide layer on another layer with a temperature between about 975° C. and 1400° C., preferably between about 1000° C. and 1200° C. Then the structure of the oxide layer is damaged, such as by ion implantation, preferably with an inert element. Thereafter the oxide layer is annealed at a temperature between about 850° C. and 900° C., preferably at about 875° C.
Inventors
- 👤 George A. Swartz
- 👤 Carl W. Benyon, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:28
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/013; H10D64/01302; H10D64/01332; H10D64/01336; H10D64/0134; H10D30/00; H10D30/60; H10D30/67; H10D30/6729; H10D30/6737; H10D30/6739; H10D64/01338; H10D64/60; H10D64/66; H10D64/68; H10P; H10P30/00; H10P30/40; H10P95/00; H10D64/01346; Y; Y10; Y10S; Y10S148/00; Y10S148/082; Y10S148/083; Y10S257/00; Y10S257/906; Y10S438/00; Y10S438/953
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
66 words
A method for making a radiation hardened oxide comprising: forming a defined first layer having an edge on a substrate; forming an oxide second layer on said first layer and on said edge to said substrate at a temperature of between about 975° C. and 1400° C.; damaging the structure of said oxide layer; and annealing said oxide layer between about 850° C. and 900° C.
Claim 2
Independent Claim
66 words
A method for making a radiation hardened oxide comprising: forming a defined first layer having an edge on a substrate; forming an oxide second layer on said first layer and on said edge to said substrate at a temperature of between about 975° C. and 1400° C.; damaging the structure of said oxide layer; and annealing said oxide layer between about 850° C. and 900° C.
Claim 3
Dependent Claim
24 words
The method of claim 1, wherein said first layer has a temperature of between about 1000° C. and 1200° C. during said forming step.
Claim 4
Dependent Claim
22 words
The method of claim 1, wherein said step of forming said second layer comprises growing said oxide layer in an oxidizing ambient.
Claim 5
Dependent Claim
16 words
The method of claim 1, wherein said oxide layer has a thickness of about 50 nm.
Claim 6
Dependent Claim
18 words
The method of claim 1, wherein said step of damaging the structure comprises ion implanting said oxide layer.
Claim 7
Dependent Claim
19 words
The method of claim 1, wherein said step of annealing is performed at a temperature of about 875° C.
Claim 8
Dependent Claim
40 words
The method of claim 1, wherein said first layer comprises a silicon mesa disposed on a sapphire substrate and further comprising: forming a gate on said oxide layer; and forming source and drain regions in said mesa adjacent said gate.
Claim 9
Dependent Claim
10 words
The method of claim 3, wherein said ambient comprises oxygen.
Claim 10
Dependent Claim
10 words
The method of claim 3, wherein said ambient comprises steam.
Claim 11
Dependent Claim
24 words
The method of claim 5, wherein said step of ion implanting comprises implanting at an areal dosage of about 3×10 14 ions/cm 2 .
Claim 12
Dependent Claim
16 words
The method of claim 5, wherein said step of ion implanting comprises implanting an inert element.
Claim 13
Dependent Claim
17 words
The method of claim 7, wherein said step of forming said gate comprises depositing and defining polysilicon.
Claim 14
Dependent Claim
21 words
The method of claim 7, wherein said step of forming source and drain regions comprises ion implanting a conductivity modifying dopant.
Claim 15
Dependent Claim
14 words
The method of claim 11, wherein said inert element comprises a noble gaseous element.
Claim 16
Dependent Claim
20 words
The method of claim 11, wherein said inert element comprises an element that is a constituent of said oxide layer.
Claim 17
Dependent Claim
23 words
The method of claim 14, wherein said noble element comprises argon implanted at an areal dosage of about 3×10 14 ions/cm 2 .
Claim 18
Dependent Claim
23 words
The method of claim 15, wherein said inert element comprises oxygen implanted at an areal dosage of about 3×10 14 ions/cm 2 .
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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) | 1990-01-05 | 1990-07-07 | 1991-01-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-05 | 1994-07-07 | 1995-01-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-05 | 1998-07-07 | 1999-01-06 | $7700.00 | Window Closed / Lapsed |