US4117094A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for silicon and trichlorosilane production
Assignee: Texas Instruments Inc
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Filing: 1977-06-13
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Granted: 1978-09-26
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Expires: 1997-06-13
Abstract
Abstract An improved method is provided for converting metallurgical grade silicon to semiconductor grade silicon, by first reacting the impure silicon with silicon tetrahalide to form a mixture of halosilanes, separating and purifying the trihalosilane, and then depositing semiconductor grade silicon by reacting the trihalosilane. The tetrahalide produced as a by-product of the deposition step is recycled to react with additional impure silicon. Improved trihalosilane yields from reacting silicon with the tetrahalide are achieved by adding hydrogen as a reactant, and by immediate quenching of the effluent with HCl. Such improved yields permit the complete system to be internally balanced so that the net production of by-products can be reduced to zero.
Inventors
- 👤 John M. Blocher, Jr.
- 👤 Melvin F. Browning
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 07:59
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/02; C01B33/08; C01B33/107; C01B33/1071
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
69 words
A method for converting silicon tetrachloride to trichlorosilane comprising the steps of: reacting silicon tetrachloride with elemental silicon at a temperature above 1400° k to form silicon dichloride, mixing hydrogen chloride with the silicon dichloride so formed to effect a stoichiometric ratio of hydrogen chloride to silicon dichloride of approximately 1:1 then quenching the dichloride-hydrogen chloride mixture to a temperature below 800° C, thereby forming trichlorosilane without polymer formation.
Claim 2
Independent Claim
69 words
A method for converting silicon tetrachloride to trichlorosilane comprising the steps of: reacting silicon tetrachloride with elemental silicon at a temperature above 1400° k to form silicon dichloride, mixing hydrogen chloride with the silicon dichloride so formed to effect a stoichiometric ratio of hydrogen chloride to silicon dichloride of approximately 1:1 then quenching the dichloride-hydrogen chloride mixture to a temperature below 800° C, thereby forming trichlorosilane without polymer formation.
Claim 3
Dependent Claim
25 words
A method as in claim 1 wherein H 2 is added to the reaction of silicon with the tetrachloride to enhance the yield of trichlorosilane.
Claim 4
Dependent Claim
14 words
A method as in claim 2 wherein the quenching is completed within one-half second.
Claim 5
Dependent Claim
14 words
A method as in claim 1 wherein the quenching is completed within one-half second.
Claim 6
Independent Claim
123 words
A method for converting metallurgical grade silicon to semiconductor grade silicon comprising the steps of: reacting metallurgical grade silicon above 1400° K with silicon tetrachloride and hydrogen to form silicon dichloride; mixing hydrogen chloride with the silicon dichloride so formed to effect a stoichiometric ratio of hydrogen chloride to silicon dichloride of approximately 1:1 quenching the dichloride-hydrogen chloride mixture to a temperature below 800° C within two seconds to form trichlorosilane, without polymer formation; purifying the trichlorosilane; converting the trichlorosilane in a deposition reactor to semiconductor grade silicon and an effluent consisting essentially of hydrogen, hydrogen chloride, silicon tetrachloride and unreacted trichlorosilane; and then separating the tetrachloride and hydrogen from the effluent and recycling said tetrachloride to react with additional metallurgical grade silicon.
Claim 7
Independent Claim
123 words
A method for converting metallurgical grade silicon to semiconductor grade silicon comprising the steps of: reacting metallurgical grade silicon above 1400° K with silicon tetrachloride and hydrogen to form silicon dichloride; mixing hydrogen chloride with the silicon dichloride so formed to effect a stoichiometric ratio of hydrogen chloride to silicon dichloride of approximately 1:1 quenching the dichloride-hydrogen chloride mixture to a temperature below 800° C within two seconds to form trichlorosilane, without polymer formation; purifying the trichlorosilane; converting the trichlorosilane in a deposition reactor to semiconductor grade silicon and an effluent consisting essentially of hydrogen, hydrogen chloride, silicon tetrachloride and unreacted trichlorosilane; and then separating the tetrachloride and hydrogen from the effluent and recycling said tetrachloride to react with additional metallurgical grade silicon.
Claim 8
Dependent Claim
14 words
A method as in claim 5 wherein the quenching is completed within one-half second.
References Cited (Backward Citations)
AU213921A
Cited
US2595620A
Cited
FR1292508A
Cited
GB924545A
Cited
US3565590A
Cited
US3824121A
Cited
US3933985A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-09-25 | 1982-03-27 | 1982-09-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-25 | 1986-03-27 | 1986-09-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-25 | 1990-03-27 | 1990-09-26 | $7700.00 | Window Closed / Lapsed |