US2999736A
Expired / Lapsed
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High purity silicon
Assignee: Houdry Process Corp
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Filing: 1959-01-07
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Granted: 1961-09-12
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Expires: 1979-01-07
Abstract
No abstract record available.
Inventors
- 👤 Shalit Harold
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:16
CPC Classifications
C; C01; C01B; C01B33/00; C01B33/08
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
102 words
THE METHOD OF PREPARING HIGH PURITY SILICON WHICH INCLUDES THE STEPS OF: PREPARING SILICON TETRAFLUORIDE, PURIFYING THE SILICON TETRAFLUORIDE BY PASSING A STREAM OF GASEOUS SILICON TETRAFLUORIDE COUNTERCURRENTLY WITH A STREAM OF ANHYDROUS LIQUID HYDROGEN FLUORIDE CONTAINING A HYDROCARBON SELECTED FROM THE GROUP CONSISTING OF META XYLENE AND MESITYLENE AND FURTHER PURIFYING THE SILICON TETRAFLUORIDE BY COOLING AT A TEMPERATURE BETWEEN -20* C. AND ABOUT -50* C. AND RECOVERING THE GASEOUS SILICON TETRAFLUORIDE FROM SUCH COOLING, WHEREBY ANY TRACE AMOUNT OF BORON TRIFLUORIDE CONTAMINANT IS REMOVED FROM THE GASEOUS SILICON TETRAFLUORIDE, AND CONVERTING THE THUS PURIFIED SILICON TETRAFLUORIDE TO HIGH PURITY SILICON.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1964-09-11 | 1965-03-13 | 1965-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-09-11 | 1969-03-13 | 1969-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-09-11 | 1973-03-13 | 1973-09-12 | $7700.00 | Window Closed / Lapsed |