US3862020A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production method for polycrystalline semiconductor bodies
Assignee: Dow Silicones Corp
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Filing: 1970-12-07
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Granted: 1975-01-21
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Expires: 1990-12-07
Abstract
Abstract Method for producing solid rods of polycrystalline semiconductor material such as silicon by thermal decomposition of vapors on interior surface of a closed end hollow form. Form is either of same material as that to be deposited or is coated with diffusion resistant layer to prevent introduction of impurities into deposited material. An injection lance is used to introduce vapors near point of closure of cylinder and is gradually withdrawn as deposition progresses.
Inventors
- 👤 Lloyd M Woerner
- 👤 Cedric G Currin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:46
CPC Classifications
C; C23; C23C; C23C8/00; C01; C01B; C01B33/00; C01B33/02; Y; Y10; Y10S; Y10S148/00; Y10S148/122
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
30 words
The method as defined in claim 1 wherein said stream of gas is carried into proximity with said closure by means of a gas injection lance introduced into the hollow.
Claim 2
Dependent Claim
46 words
The method as defined in claim 2 and further including withdrawing said lance from said hollow aT a rate substantially equal to the rate of deposition of the semiconductor material on said closure, whereby the hollow in the cylinder is gradually filled with said semiconductor material.
Claim 3
Dependent Claim
38 words
The method defined in claim 1 wherein said closure is initially provided at substantially the center of said cylinder and lances are introduced from both ends of the cylinder thereby providing deposition on both sides of said closure.
Claim 4
Dependent Claim
19 words
The method defined in claim 4 wherein a multiplicity of said cylinders are heated from a single heat source.
Claim 5
Dependent Claim
19 words
The method defined in claim 2 wherein a multiplicity of said cylinders are heated from a single heat source.
Claim 6
Independent Claim
147 words
The method of making solid rods of semiconductor grade silicon by chemical vapor deposition which comprises: making a hollow cylinder of material capable of withstanding the deposition temperatures of silicon from the vapor phase without substantial deformation or decomposition, closing the hollow in said cylinder at one portion along the length thereof with a cylindrical body of said semiconductor material having an axial length which is short in comparison to the length of said cylinder, heating said cylinder, directing a stream of a heat decomposable gas consisting of silicon and one or more of the elements hydrogen, chlorine and bromine against the closure in said cylinder while said cylinder is heated to the decomposition temperature of said gas, whereby silicon is deposited on said closure and the adjacent walls of the hollow in said cylinder, and removing the original cylinder material from the silicon body thus formed.
Claim 7
Dependent Claim
30 words
The method as defined in claim 7 wherein said stream of gas is carried into proximity with said closure by means of a gas injection lance introduced into the hollow.
Claim 8
Dependent Claim
42 words
The method as defined in claim 8 and further including withdrawing said lance from said hollow at a rate substantially equal to the rate of deposition of silicon on said closure, whereby the hollow in the cylinder is gradually filled with silicon.
Claim 9
Dependent Claim
45 words
The method as defined in claim 7 and further including prior to introducing said thermally decomposable gas into said cylinder, coating the internal surfaces of said cylinder with a diffusion resistant layer to prevent diffusion from said cylinder into the silicon deposited in later steps.
Claim 10
Dependent Claim
34 words
The method as defined in claim 10 wherein a layer of silicon is deposited on said internal surfaces of said cylinder and the internal surface of said layer is oxidized to form said coating.
Claim 11
Dependent Claim
31 words
The method as defined in claim 11 wherein a plurality of alternating layers of silicon and silicon oxide are applied to form said coating on the internal surfaces of said cylinder.
Claim 12
Dependent Claim
20 words
The method as defined in claim 10 wherein silicon carbide forms said coating on the internal surfaces of said cylinder.
Claim 13
Dependent Claim
53 words
The method as defined in claim 13 wherein said cylinder is graphite and said silicon carbide is formed by depositing a layer of silicon on the surface of said graphite and then raising the temperature of said cylinder to cause said silicon to melt into and react with the carbon of said graphite.
Claim 14
Dependent Claim
28 words
The method as defined in claim 14 and further including forming an additional layer of silicon oxide on the surface of said silicon carbide to form said coating.
Claim 15
Dependent Claim
28 words
The method as defined in claim 13 wherein a plurality of alternating layers of silicon and silicon oxide are applied over said silicon carbide to form said coating.
Claim 16
Dependent Claim
34 words
The method as defined in claim 8 including the step of continuously cooling said lance to a temperature below the decomposition point of said gas to prevent deposition internally thereof while injecting gas therethrough.
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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) | 1978-01-20 | 1978-07-22 | 1979-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-20 | 1982-07-22 | 1983-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-20 | 1986-07-22 | 1987-01-21 | $7700.00 | Window Closed / Lapsed |