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US4722764A
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Method for the manufacture of dislocation-free monocrystalline silicon rods
Assignee: Siltronic AG
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Filing: 1986-05-01
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Granted: 1988-02-02
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Expires: 2006-05-01
Abstract
Abstract A method for crucible-free zone pulling of silicon monocrystalline rods is described. According to the invention, a polycrystalline silicon rod obtained by crucible pulling according to the Czochralski procedure is used in lieu of the polycrystalline silicon rod produced by vapor deposition.
Inventors
- 👤 Heinz Herzer
- 👤 Wolfgang Hensel
- 👤 Gunter Matuszak
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:45
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/02; C30B29/06; C30B13/00
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
80 words
In a method for the manufacture of a dislocation-free monocrystalline silicon rod by a crucible-free float zoning of a polycrystalline silicon supply rod, the improvement comprising the step of using a Czochralski grown polycrystalline silicon rod as the supply rod, subjecting it to a single floating zone pass, whereby a dislocation-free monocrystalline rod is obtained, and wherein the cross-sectional surface of the polycrystalline rod is substantially composed of monocrystalline regions comprising less than about 1/3 of the entire cross-sectional surface.
Claim 2
Dependent Claim
80 words
In a method for the manufacture of a dislocation-free monocrystalline silicon rod by a crucible-free float zoning of a polycrystalline silicon supply rod, the improvement comprising the step of using a Czochralski grown polycrystalline silicon rod as the supply rod, subjecting it to a single floating zone pass, whereby a dislocation-free monocrystalline rod is obtained, and wherein the cross-sectional surface of the polycrystalline rod is substantially composed of monocrystalline regions comprising less than about 1/3 of the entire cross-sectional surface.
Claim 3
Dependent Claim
29 words
The method of claim 1, wherein the diameter of said supply rod is so selected that it differs by at most 20% from that of the desired monocrystalline rod.
Claim 4
Dependent Claim
21 words
The method of claim 1, additionally including the step of forming a bulge on one end of said polycrystalline supply rod.
Claim 5
Dependent Claim
17 words
The method of claim 1, wherein said supply rod has a diameter of at least 100 mm.
Claim 6
Dependent Claim
19 words
The method of claim 1, wherein said supply rod was pulled at a speed of 1.5 to 2.5 mm/min.
Claim 7
Dependent Claim
39 words
The method according to claim 1, wherein said polycrystalline silicon rod is produced from polycrystalline silicon obtained by vapor deposition of trichlorosilane on a heated carrier element, waste pieces of floating zone produced silicon rods, and a combination thereof.
References Cited (Backward Citations)
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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) | 1991-02-01 | 1991-08-03 | 1992-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-01 | 1995-08-03 | 1996-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-01 | 1999-08-03 | 2000-02-02 | $7700.00 | Window Closed / Lapsed |