US4247859A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Epitaxially grown silicon layers with relatively long minority carrier lifetimes
Assignee: Northrop Grumman Corp
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Filing: 1974-11-29
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Granted: 1981-01-27
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Expires: 1994-11-29
Abstract
Abstract A semiconductor device such as a film or hybrid integrated circuit is provided having a relatively lightly doped, epitaxially grown silicon layer with a relatively long minority carrier lifetime. The lightly doped silicon layer of less than about 1x1017 per cm3 is grown on a heavily doped silicon layer of greater than about 1x1019 and preferably greater than about 1x1020 per cm3 formed with phosphorus or boron impurity. The heavily doped silicon layer is preferably formed, either in a semiconductor body or an epitaxial layer on an insulator substrate, preferably by diffusing the impurity into the body or epitaxial layer. Preferably, the semiconductor device is a thin-film device and most desirably a silicon-on-sapphire device.
Inventors
- 👤 Prosenjit Rai-Choudhury
- 👤 Dieter K. Schroder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:43
CPC Classifications
H; H10; H10D; H10D86/00; H10D10/00; H10D10/311; H10D10/40; H10D10/441; H10D84/00; H10D84/80; H10D84/82; H10D84/83; H10D84/85
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
100 words
A silicon-on-sapphire semiconductor having a region with a relatively long minority carrier lifetime comprised of: (a) a sapphire substrate with a major surface; (b) a heavily doped epitaxial silicon layer with a surface impurity concentration greater than about 1×10 19 per cm 3 of phosphorus impurity over the major surface of the sapphire substrate; and (c) a relatively lightly doped epitaxial silicon layer with an impurity concentration less than about 1×10 17 per cm 3 adjoining the heavily doped epitaxial silicon layer, said lightly doped epitaxial silicon layer having a relatively long minority carrier lifetime of greater than 50 nanoseconds.
Claim 2
Dependent Claim
100 words
A silicon-on-sapphire semiconductor having a region with a relatively long minority carrier lifetime comprised of: (a) a sapphire substrate with a major surface; (b) a heavily doped epitaxial silicon layer with a surface impurity concentration greater than about 1×10 19 per cm 3 of phosphorus impurity over the major surface of the sapphire substrate; and (c) a relatively lightly doped epitaxial silicon layer with an impurity concentration less than about 1×10 17 per cm 3 adjoining the heavily doped epitaxial silicon layer, said lightly doped epitaxial silicon layer having a relatively long minority carrier lifetime of greater than 50 nanoseconds.
Claim 3
Dependent Claim
101 words
A silicon-on-sapphire semiconductor device having a region with a relatively long minority carrier lifetime comprised of: (a) a sapphire substrate with a major surface; (b) a heavily doped epitaxial silicon layer with a surface impurity concentration greater than about 1×10 20 per cm 3 of phosphorus impurity over the major surface of the sapphire substrate; and (c) a relatively lightly doped epitaxial silicon layer with an impurity concentration less than about 1×10 17 per cm 3 adjoining the heavily doped epitaxial silicon layer, said lightly doped epitaxial silicon layer having a relatively long minority carrier lifetime of greater than 50 nanoseconds.
Claim 4
Dependent Claim
101 words
A silicon-on-sapphire semiconductor device having a region with a relatively long minority carrier lifetime comprised of: (a) a sapphire substrate with a major surface; (b) a heavily doped epitaxial silicon layer with a surface impurity concentration greater than about 1×10 20 per cm 3 of phosphorus impurity over the major surface of the sapphire substrate; and (c) a relatively lightly doped epitaxial silicon layer with an impurity concentration less than about 1×10 17 per cm 3 adjoining the heavily doped epitaxial silicon layer, said lightly doped epitaxial silicon layer having a relatively long minority carrier lifetime of greater than 50 nanoseconds.
Claim 5
Dependent Claim
101 words
A silicon-on-sapphire semiconductor device having a region with a relatively long minority carrier lifetime comprised of: (a) a sapphire substrate with a major surface; (b) a heavily doped epitaxial silicon layer with a surface impurity concentration greater than about 1×10 19 per cm 3 of boron impurity over the major surface of the sapphire substrate; and (c) a relatively lightly doped epitaxial silicon layer with an impurity concentration less than about 1×10 17 per cm 3 adjoining the heavily doped epitaxial silicon layer, said lightly doped epitaxial silicon layer having a relatively long minority carrier lifetime of greater than 50 nanoseconds.
Claim 6
Dependent Claim
101 words
A silicon-on-sapphire semiconductor device having a region with a relatively long minority carrier lifetime comprised of: (a) a sapphire substrate with a major surface; (b) a heavily doped epitaxial silicon layer with a surface impurity concentration greater than about 1×10 19 per cm 3 of boron impurity over the major surface of the sapphire substrate; and (c) a relatively lightly doped epitaxial silicon layer with an impurity concentration less than about 1×10 17 per cm 3 adjoining the heavily doped epitaxial silicon layer, said lightly doped epitaxial silicon layer having a relatively long minority carrier lifetime of greater than 50 nanoseconds.
References Cited (Backward Citations)
US3237062A
Cited
US3418181A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-27 | 1984-07-28 | 1985-01-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-27 | 1988-07-28 | 1989-01-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-27 | 1992-07-28 | 1993-01-27 | $7700.00 | Window Closed / Lapsed |