US5340434A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing silicon single crystal
Assignee: Shin-Etsu Handotai Co Ltd
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Filing: 1993-02-01
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Granted: 1994-08-23
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Expires: 2013-02-01
Abstract
Abstract A process for producing a silicon single crystal is disclosed which comprises the steps of providing a silicon melt in a crucible, feeding grains of silicon polycrystal to the silicon melt and pulling up a silicon single crystal from the silicon melt. The concentration of residual hydrogen in the grains of silicon polycrystal is more than 10 ppmwt and less than 100 ppmwt. The process prevents the silicon single crystal from being polycrystalline.
Inventors
- 👤 Kiyotaka Takano
- 👤 Izumi Fusegawa
- 👤 Hirotoshi Yamagishi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 14:18
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/02; C30B29/06; C30B15/00
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
60 words
A process for producing a silicon single crystal, comprising the steps of: providing a silicon melt in a crucible; feeding grains of silicon polycrystal to the silicon melt, the concentration of residual hydrogen in the grains of silicon polycrystal being more than 10 ppmwt and less than 100 ppmwt; and pulling up a silicon single crystal from the silicon melt.
Claim 2
Dependent Claim
60 words
A process for producing a silicon single crystal, comprising the steps of: providing a silicon melt in a crucible; feeding grains of silicon polycrystal to the silicon melt, the concentration of residual hydrogen in the grains of silicon polycrystal being more than 10 ppmwt and less than 100 ppmwt; and pulling up a silicon single crystal from the silicon melt.
Claim 3
Dependent Claim
74 words
A process for producing a silicon single crystal, comprising the steps of: providing a silicon melt in a crucible; continuously feeding a controlled amount of grains of silicon polycrystal to the silicon melt concurrently with a growth of a silicon single crystal, the concentration of residual hydrogen in the grains of silicon polycrystal being more than 10 ppmwt and less than 100 ppmwt; and pulling up the silicon single crystal from the silicon melt.
Claim 4
Dependent Claim
74 words
A process for producing a silicon single crystal, comprising the steps of: providing a silicon melt in a crucible; continuously feeding a controlled amount of grains of silicon polycrystal to the silicon melt concurrently with a growth of a silicon single crystal, the concentration of residual hydrogen in the grains of silicon polycrystal being more than 10 ppmwt and less than 100 ppmwt; and pulling up the silicon single crystal from the silicon melt.
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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) | 1997-08-22 | 1998-02-21 | 1998-08-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-08-22 | 2002-02-21 | 2002-08-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-08-22 | 2006-02-21 | 2006-08-23 | $7700.00 | Window Closed / Lapsed |