US5189508A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silicon wafer excelling in gettering ability and method for production thereof
Assignee: Siltronic Japan Corp
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Filing: 1991-10-31
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Granted: 1993-02-23
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Expires: 2011-10-31
Abstract
Abstract A silicon wafer comprising a substrate of single crystal silicon, a silicon oxide film 1 to 8 Å in thickness formed on one surface of said substrate, and a polysilicon layer formed on said silicon oxide film and possessing an excellent gettering ability, is prepared by oxidizing single crystal silicon, thereby forming a silicon oxide film 1 to 8 Å in thickness on said surface, and exposing said silicon oxide film to a gaseous silane at an elevated temperature, thereby forming a polysilicon layer on said silicon oxide film.
Inventors
- 👤 Masaharu Tachimori
- 👤 Kazunori Ishizaka
- 👤 Hideo Araki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:55
CPC Classifications
H; H10; H10P; H10P36/00; H10P36/03; Y; Y10; Y10S; Y10S257/00; Y10S257/913
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
73 words
A silicon wafer possessing an excellent ability of gettering impurities from a single crystal silicon semiconductor, comprising: a substrate of single crystal silicon for forming devices therein; a silicon oxide film 1 to 8 Å in thickness, formed on one surface of said substrate, providing countless nuclei necessary for uniform growth of a polycrystalline film; and a polysilicon film formed on said silicon oxide film as a getter of impurities in said substrate.
Claim 2
Dependent Claim
73 words
A silicon wafer possessing an excellent ability of gettering impurities from a single crystal silicon semiconductor, comprising: a substrate of single crystal silicon for forming devices therein; a silicon oxide film 1 to 8 Å in thickness, formed on one surface of said substrate, providing countless nuclei necessary for uniform growth of a polycrystalline film; and a polysilicon film formed on said silicon oxide film as a getter of impurities in said substrate.
Claim 3
Dependent Claim
23 words
A silicon wafer according to claim 1, wherein said silicon oxide film has a thickness in the range of 1 to 5 Å.
Claim 4
Dependent Claim
22 words
A silicon wafer according to claim 2, wherein said polysilicon film has a thickness in the range of 5,000 Å to 1.5μm.
Claim 5
Dependent Claim
23 words
A silicon wafer according to claim 1, wherein said polysilicon film has a thickness in the range of 1,000 Å to 5 μm.
Claim 6
Dependent Claim
22 words
A silicon wafer according to claim 1, wherein said polysilicon film has crystalline grains with a diameter of 0.1 to 0.4 micron.
Claim 7
Dependent Claim
18 words
A silicon wafer according to claim 1, wherein said substrate has a thickness of 300 to 1,000 microns.
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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) | 1996-02-23 | 1996-08-24 | 1997-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-02-23 | 2000-08-24 | 2001-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-02-23 | 2004-08-24 | 2005-02-23 | $7700.00 | Window Closed / Lapsed |