US4378269A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of manufacturing a single crystal silicon rod
Assignee: Toshiba Corp
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Filing: 1981-06-24
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Granted: 1983-03-29
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Expires: 2001-06-24
Abstract
Abstract A method of manufacturing a single crystal silicon rod by the pulling method which is characterized in that the intracrystal temperature of the growing single crystal silicon rod is reduced from 900° to 500° C. in less than 4 hours.
Inventors
- 👤 Yoshiaki Matsushita
- 👤 Shinichiro Takasu
- 👤 Seigo Kishino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:52
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/02; C30B29/06; C30B15/00; C30B15/14; C30B15/20; C30B15/206
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
107 words
A method for manufacturing a single crystal silicon rod having a diameter of 80 mm or more comprising the steps of: pulling up a seed silicon crystal contacted by a silicon melt in an atmosphere of protective gas, lowering the temperature of said rod directly to about 900° C., reducing the susceptibility of said silicon rod to formation of dislocation by subsequent thermal treatments by then reducing the intracrystal temperature of the growing single crystal silicon rod from 900° C. to 500° C. in less than 4 hours and maintaining the intracrystal temperature gradient of said single crystal silicon rod at a value less than 100° C./cm.
Claim 2
Independent Claim
107 words
A method for manufacturing a single crystal silicon rod having a diameter of 80 mm or more comprising the steps of: pulling up a seed silicon crystal contacted by a silicon melt in an atmosphere of protective gas, lowering the temperature of said rod directly to about 900° C., reducing the susceptibility of said silicon rod to formation of dislocation by subsequent thermal treatments by then reducing the intracrystal temperature of the growing single crystal silicon rod from 900° C. to 500° C. in less than 4 hours and maintaining the intracrystal temperature gradient of said single crystal silicon rod at a value less than 100° C./cm.
Claim 3
Dependent Claim
15 words
The method according to claim 1, wherein the intracrystal temperature gradient is about 50° C./cm.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-28 | 1986-09-27 | 1987-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-28 | 1990-09-27 | 1991-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-28 | 1994-09-27 | 1995-03-29 | $7700.00 | Window Closed / Lapsed |