US4415401A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control of atmosphere surrounding crystal growth zone
Assignee: Schott Solar CSP Inc
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Filing: 1980-12-15
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Granted: 1983-11-15
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Expires: 2000-12-15
Abstract
Abstract The invention pertains to growth of silicon bodies from a melt and comprises enveloping the liquid/solid interface with a mixture of an inert gas and more than a trace amount of a carbon-containing gas. The carbon-containing gas may be a compound of carbon and oxygen such as CO or CO2, and oxygen gas also may be introduced to the growth zone.
Inventors
- 👤 Fritz Wald
- 👤 Juris P. Kalejs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 06:37
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/02; C30B29/06; C30B15/00; C30B15/34; Y; Y10; Y10S; Y10S117/00; Y10S117/906
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
88 words
In a method of growing a crystallized body of silicon from a silicon melt where a stationary graphite shaping member is used in the growth zone and the liquid/solid growth interface is characterized by a meniscus between the shaping member and the growing body, the improvement comprising continuously enveloping the growth zone with a moving mixture of an inert gas and a carbon-containing gas, said carbon-containing gas constituting a relatively small proportion of said mixture so as to beneficially affect the electronic quality of the grown silicon body.
Claim 2
Dependent Claim
88 words
In a method of growing a crystallized body of silicon from a silicon melt where a stationary graphite shaping member is used in the growth zone and the liquid/solid growth interface is characterized by a meniscus between the shaping member and the growing body, the improvement comprising continuously enveloping the growth zone with a moving mixture of an inert gas and a carbon-containing gas, said carbon-containing gas constituting a relatively small proportion of said mixture so as to beneficially affect the electronic quality of the grown silicon body.
Claim 3
Dependent Claim
19 words
A method according to claim 1 wherein said carbon-containing gas is carbon monoxide, carbon dioxide or a mixture thereof.
Claim 4
Dependent Claim
11 words
Method according to claim 1 wherein said carbon-containing gas comprises CO.
Claim 5
Dependent Claim
13 words
Method according to claim 1 wherein said carbon-containing gas comprises CO 2 .
Claim 6
Dependent Claim
27 words
Method according to claim 2 wherein said mixture of said inert gas and said carbon-containing gas contains between about 25 and 5000 ppm of said carbon-containing gas.
Claim 7
Dependent Claim
14 words
A method according to claim 1, wherein said inert gas is argon or helium.
Claim 8
Dependent Claim
44 words
A method according to claim 1 wherein said inert gas and carbon-containing gas are introduced to said growth zone so as to maintain a concentration of said carbon-containing gas in the atmosphere surrounding said growth zone of between about 25 and about 5000 ppm.
Claim 9
Dependent Claim
13 words
Method according to claim 1 wherein said shaping member is a capillary die.
Claim 10
Dependent Claim
15 words
Method according to claim 8 wherein said shaping member is located in a graphite crucible.
Claim 11
Dependent Claim
17 words
Method according to claim 1 further including the step of introducing oxygen gas to the growth zone.
Claim 12
Dependent Claim
18 words
Method according to claim 10 wherein the carbon-containing gas is CO or CO 2 or a mixture thereof.
Claim 13
Dependent Claim
24 words
Method according to claim 2 wherein said shaping member is disposed in a graphite crucible and said shaping member is heated by graphite heaters.
Claim 14
Dependent Claim
33 words
A method according to claim 2 wherein said growth zone is a furnace and said mixture of an inert gas and said carbon-containing gas is circulated through said furnace via said growth zone.
Claim 15
Dependent Claim
46 words
A method according to claim 1 wherein said shaping member is disposed in a furnace and a gas comprising at least one member of the class consistingof carbon and oxygen is introduced to said furnace via at least one passageway terminating close to said growing body.
Claim 16
Dependent Claim
15 words
A method according to claim 2 wherein said passageway is located above said shaping member.
Claim 17
Dependent Claim
51 words
A method according to claim 1 wherein said silicon body is in the shape of a flat ribbon and a carbon and oxygen-containing gas is introduced to said growth zone via at least two orifices terminating close to the upper end of said shaping member on opposite sides of said ribbon.
Claim 18
Dependent Claim
64 words
A method according to claim 13 wherein a gaseous stream comprising argon or helium is introduced to said furnace via an inlet located below said growth zone, and a mixture of argon or helium and a gas from the class consisting of CO and CO 2 is introduced directly to said growth zone via one or more passageways terminating close to said growth zone.
Claim 19
Dependent Claim
33 words
A method according to claim 2 wherein said crystallized body is grown above said graphite shaping member and said at least one passageway is located above but close to said graphite shaping member.
Claim 20
Dependent Claim
14 words
A method according to claim 8 wherein said inert gas is helium or argon.
Claim 21
Dependent Claim
66 words
A method according to claim 1 wherein said carbon-containing gas comprises at least one member of the group consisting of carbon monoxide and carbon dioxide and the concentration of said carbon-containing gas in the growth zone is maintained at a level which will promote the formation of a film comprising SiO x on the crystallized body, where X has a value of between 1 and 2.
Claim 22
Dependent Claim
19 words
A method according to claim 20 wherein said film has a thickness of between about 200 and 600 angstroms.
Claim 23
Dependent Claim
34 words
A method according to claim 2 wherein said growth zone includes said menisucs and at least some of said carbon-containing gas is delivered to said growth zone by passageways terminating close to said meniscus.
Claim 24
Dependent Claim
102 words
In a method of growing a crystallized ribbon of silicon where a stationary graphite capillary die is used to supply liquid silicon to the growth zone and the liquid/solid growth interface is characterized by a meniscus between the capillary die and the growing ribbon, the improvement comprising establishing and maintaining in the growth zone about the liquid/solid growth interface a gaseous environment consisting of argon or helium and a gaseous compound of carbon and oxygen, with the concentration of said gaseous compound being between about 25 and about 500 ppm so as to beneficially affect the electronic quality of the grown ribbon.
Claim 25
Dependent Claim
102 words
In a method of growing a crystallized ribbon of silicon where a stationary graphite capillary die is used to supply liquid silicon to the growth zone and the liquid/solid growth interface is characterized by a meniscus between the capillary die and the growing ribbon, the improvement comprising establishing and maintaining in the growth zone about the liquid/solid growth interface a gaseous environment consisting of argon or helium and a gaseous compound of carbon and oxygen, with the concentration of said gaseous compound being between about 25 and about 500 ppm so as to beneficially affect the electronic quality of the grown ribbon.
Claim 26
Dependent Claim
37 words
A method according to claim 2 wherein at least some of said mixture of an inert gas and a carbon-containing gas is introduced to said growth zone via at least one passageway terminating close to said interface.
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) | 1986-11-14 | 1987-05-16 | 1987-11-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-11-14 | 1991-05-16 | 1991-11-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-11-14 | 1995-05-16 | 1995-11-15 | $7700.00 | Window Closed / Lapsed |