US4239585A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the production of high purity silicon monocrystals having a low oxygen content
Assignee: Siltronic AG
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Filing: 1978-10-25
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Granted: 1980-12-16
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Expires: 1998-10-25
Abstract
Abstract The invention provides a process according to which the oxygen content in crucible-drawn silicon crystals can be lowered and kept substantially constant throughout the length of the rod. This is achieved in that, after applying the seed crystal to the melt pool, the silicon rod being drawn from the melt pool is initially rotated at a speed from 3 to 6 rev/min and this rotational speed is preferably increased to higher values during the drawing process.
Inventors
- 👤 Franz Kohl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 09:08
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/02; C30B29/06; C30B15/00; C30B15/30
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
111 words
An improved process for the production of high purity silicon monocrystals having a low oxygen content of the Czochralski crucible-drawing type wherein polycrystalline silicon is melted in a crucible to produce a melt and a seed crystal is then dipped into the melt and is continuously drawn therefrom while being rotated so as to produce a growing monocrystalline silicon rod, which is withdrawn from the melt, the improvement comprising: initially withdrawing the crystallized silicon rod from the melt while rotating said rod at a speed within the range of from 3 to 6 rev/min and increasing the rotational speed by 0.5 to 2 rev/min per 10 cm of crystallized silicon rod.
Claim 2
Dependent Claim
111 words
An improved process for the production of high purity silicon monocrystals having a low oxygen content of the Czochralski crucible-drawing type wherein polycrystalline silicon is melted in a crucible to produce a melt and a seed crystal is then dipped into the melt and is continuously drawn therefrom while being rotated so as to produce a growing monocrystalline silicon rod, which is withdrawn from the melt, the improvement comprising: initially withdrawing the crystallized silicon rod from the melt while rotating said rod at a speed within the range of from 3 to 6 rev/min and increasing the rotational speed by 0.5 to 2 rev/min per 10 cm of crystallized silicon rod.
Claim 3
Dependent Claim
18 words
The process according to claim 1, wherein said speed of rotation of said silicon rod is increased continuously.
Claim 4
Dependent Claim
22 words
The process according to claim 1, wherein said speed or rotation of said silicon rod is increased continuously at a uniform rate.
References Cited (Backward Citations)
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Cited
US3275417A
Cited
US3929557A
Cited
DE2619965A1
Cited
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Cited
US4040895A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-16 | 1984-06-16 | 1984-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-16 | 1988-06-16 | 1988-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-16 | 1992-06-16 | 1992-12-16 | $7700.00 | Window Closed / Lapsed |