US4952425A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing high purity dopant alloys
Assignee: Albemarle Corp
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Filing: 1988-06-27
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Granted: 1990-08-28
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Expires: 2008-06-27
Abstract
Abstract Particles of silicon and a p or n carrier substance which are in spherical or spheroidal form, and suitable for use in the preparation of doped semiconductor devices, can be prepared by a fluidized bed technique for chemical vapor deposition of a carrier substance (B, P, As or Sb). The prepared products have a kernel of high purity polysilicon and a layer of silicon/dopant alloy upon the kernel. Optionally, the particles have a thin outer layer of silicon.
Inventors
- 👤 Robert H. Allen
- 👤 Jameel Ibrahim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 19:30
CPC Classifications
B; B01; B01J; B01J2/00; B01J2/003; B01J2/16; C; C23; C23C; C23C16/00; C23C16/22; C23C16/24; C23C16/44; C23C16/442
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
134 words
A fluidized bed process for producing a particulate product having a nucleus or center portion of high purity elemental silicon and a substantially silicon-free layer deposited on said nucleus or center portion of at least one of a p or n carrier element, said process consisting essentially of passing a stream of deposition gas consisting essentially of binary hydride or halide of at least one of a p or n carrier element and an inert diluent carrier gas through a fluidized bed of substantially spherical particles of high purity elemental silicon in free flowing particulate form at a temperature above the decomposition temperature of said hydride or halide whereby said substantially silicon-free layer of at least one of a p or n carrier element is deposited on said particles of high purity elemental silicon.
Claim 2
Dependent Claim
134 words
A fluidized bed process for producing a particulate product having a nucleus or center portion of high purity elemental silicon and a substantially silicon-free layer deposited on said nucleus or center portion of at least one of a p or n carrier element, said process consisting essentially of passing a stream of deposition gas consisting essentially of binary hydride or halide of at least one of a p or n carrier element and an inert diluent carrier gas through a fluidized bed of substantially spherical particles of high purity elemental silicon in free flowing particulate form at a temperature above the decomposition temperature of said hydride or halide whereby said substantially silicon-free layer of at least one of a p or n carrier element is deposited on said particles of high purity elemental silicon.
Claim 3
Dependent Claim
30 words
The process of claim 1 wherein said particles of high purity elemental silicon are formed in a fluidized bed by chemical vapor deposition of silicon on fluidized silicon seed particles.
Claim 4
Dependent Claim
30 words
The process of claim 1 which includes depositing an outer layer of silicon on said deposited substantially silicon-free layer of at least one of a p or n carrier element.
Claim 5
Dependent Claim
20 words
The process of claim 1 wherein said particles of high purity elemental silicon have a size distribution of 500-600 microns.
Claim 6
Dependent Claim
20 words
The process of claim 1 wherein said particles of high purity elemental silicon have a size distribution of 450-500 microns.
Claim 7
Dependent Claim
20 words
The process of claim 1 wherein said particles of high purity elemental silicon have a size distribution of 500-600 microns.
Claim 8
Dependent Claim
25 words
The process of claim 1 wherein said carrier element is present in said product in an amount ranging from about 10 to about 3000 ppma.
Claim 9
Dependent Claim
19 words
The process of claim 1 wherein said particulate product has a diameter ranging from about 100 to 2000 microns.
Claim 10
Dependent Claim
22 words
The process of claim 3 wherein said outer layer of silicon has a thickness ranging from about 1 to about 10 microns.
Claim 11
Dependent Claim
36 words
The process of claim 1 wherein said binary hydride or halide is selected from B 2 H 6 , PH 3 , A 5 H 3 , SbH 3 , Bcl 3 and Pcl 3 .
Claim 12
Dependent Claim
25 words
The process of claim 1 wherein said layer of at least one of a p and n carrier has a thickness less than 150 microns.
Claim 13
Dependent Claim
29 words
The process of claim 1 wherein said layer of at least one of a p and n carrier has a thickness of from about 5 to about 100 microns.
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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) | 1993-08-27 | 1994-02-26 | 1994-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-27 | 1998-02-26 | 1998-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-27 | 2002-02-26 | 2002-08-28 | $7700.00 | Window Closed / Lapsed |