Patent US4141779A successfully refreshed from Google Patents.
US4141779A
Expired / Lapsed
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Method and apparatus for avoiding undesirable deposits in crystal growing operations
Assignee: AT&T Inc
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Filing: 1978-05-12
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Granted: 1979-02-27
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Expires: 1998-05-12
Abstract
Abstract In Czochralski crystal growing operations, particularly those involving growth of silicon crystals, projecting formations of silicon monoxide sometimes form on the surface of the melt-containing crucible just above the initial level of the melt. These formations are avoided by perturbing chemical formation conditions at the region of probable formation. Such perturbations may be provided by a tube through which either a positive pressure of a gas, such as argon, is directed toward the region of probable formation or through which a negative pressure may be applied to perturb the formation conditions.
Inventors
- 👤 David W. Hill
- 👤 Lewis E. Katz
- 👤 Robert J. Lavigna
- 👤 Raymond E. Reusser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:18
CPC Classifications
C; C30; C30B; C30B15/00; C30B15/20; Y; Y10; Y10T; Y10T117/00; Y10T117/10; Y10T117/1024; Y10T117/1032; Y10T117/1068
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
114 words
Apparatus for growing crystalline material from a melt comprising: a crucible for containing a material for making the melt; means for producing ambient conditions above the melt; means for heating a given quantity of material in the crucible to a temperature at which it melts; means for supporting a crystalline body of the material with respect to the melt; and means, separate from the ambient conditions' producing means and located adjacent to a specific portion of the crucible where undesirable material tends to form, for selectively intensifying perturbation of the ambient conditions at such specific portion which is located above the surface of the melt, sufficiently intense to prevent undesirable formation of material thereupon.
Claim 2
Dependent Claim
114 words
Apparatus for growing crystalline material from a melt comprising: a crucible for containing a material for making the melt; means for producing ambient conditions above the melt; means for heating a given quantity of material in the crucible to a temperature at which it melts; means for supporting a crystalline body of the material with respect to the melt; and means, separate from the ambient conditions' producing means and located adjacent to a specific portion of the crucible where undesirable material tends to form, for selectively intensifying perturbation of the ambient conditions at such specific portion which is located above the surface of the melt, sufficiently intense to prevent undesirable formation of material thereupon.
Claim 3
Dependent Claim
30 words
Apparatus as recited in claim 1, wherein the perturbing means include means for supplying a positive pressure of a gas to the portion of the inner wall of the crucible.
Claim 4
Dependent Claim
76 words
Apparatus as recited in claim 2, further comprising means for supporting the crucible including means for rotating the crucible; wherein the ambient conditions' producing means establishes an environment of positive pressure with respect to atmospheric pressure; and wherein the supplying means includes an immobile tube, the opening of which is adjacent to the portion of the inner wall of the crucible, and through which the gas is directed upon said portion as the crucible is rotated.
Claim 5
Dependent Claim
27 words
Apparatus as recited in claim 1, wherein the perturbing means includes means for supplying a negative pressure to the portion of the inner wall of the crucible.
Claim 6
Dependent Claim
54 words
Apparatus as recited in claim 4, further comprising means for supporting the crucible, said supporting means including means for rotating the crucible; wherein the supplying means includes an immobile tube directed upon the portion of the inner wall of the crucible as the crucible is rotated and through which a negative pressure is drawn.
Claim 7
Independent Claim
105 words
A method of growing crystalline material from a melt comprising: heating a quantity of a material in a crucible to a temperature at which it melts; producing ambient conditions above the melt; withdrawing and supporting a crystalline body of material with respect to the melt; and selectively intensifying perturbation of the ambient conditions with a means separate from the means that produces such conditions, the intensifying of perturbation occurring at a specific portion of the inner wall of the crucible where undesired material tends to form, which portion is located above the surface of the melt, sufficiently intense to prevent undesirable formations of material thereupon.
Claim 8
Independent Claim
105 words
A method of growing crystalline material from a melt comprising: heating a quantity of a material in a crucible to a temperature at which it melts; producing ambient conditions above the melt; withdrawing and supporting a crystalline body of material with respect to the melt; and selectively intensifying perturbation of the ambient conditions with a means separate from the means that produces such conditions, the intensifying of perturbation occurring at a specific portion of the inner wall of the crucible where undesired material tends to form, which portion is located above the surface of the melt, sufficiently intense to prevent undesirable formations of material thereupon.
Claim 9
Dependent Claim
36 words
A method as recited in claim 6, wherein the perturbing step includes directing a positive pressure of a gas upon a portion of the inner wall of the crucible above the level of the melt surface.
Claim 10
Dependent Claim
56 words
A method as recited in claim 7, comprising the further steps of maintaining the ambient conditions above the melt at a positive pressure with respect to atmospheric pressure, and of rotating the crucible with respect to the stream of gas so that the gas is effective upon an annular portion of the wall of the crucible.
Claim 11
Dependent Claim
26 words
A method as recited in claim 6, wherein the perturbing step includes providing a negative pressure to a portion of the inner wall of the crucible.
Claim 12
Dependent Claim
33 words
A method as recited in claim 9, wherein the crucible is rotated with respect to the negative pressure so that the negative pressure is effective upon an annular portion of the inner wall.
References Cited (Backward Citations)
US3353914A
Cited
US4036595A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-02-26 | 1982-08-28 | 1983-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-02-26 | 1986-08-28 | 1987-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-02-26 | 1990-08-28 | 1991-02-27 | $7700.00 | Window Closed / Lapsed |