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Patent US4512954A successfully refreshed from Google Patents.
US4512954A
Expired / Lapsed
US
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Crystal growing apparatus
Assignee: Toshiba Corp
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Filing: 1983-08-10
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Granted: 1985-04-23
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Expires: 2003-08-10
Abstract
Abstract In a crystal growing apparatus, an electrode is arranged above a crystal raw material melt at a distance therefrom. Changes in the resistance of the atmosphere between the electrode and the melt are detected so as to detect the surface level of the melt. The crystal pulling speed or power supply for heating the melt is controlled in accordance with the detection result, thereby performing dimension control of the crystal.
Inventors
- 👤 Toshiro Matsui
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 10:36
CPC Classifications
C; C30; C30B; C30B15/00; C30B15/20; C30B15/22; Y; Y10; Y10T; Y10T117/00; Y10T117/10; Y10T117/1004; Y10T117/1008; Y10T117/1024; Y10T117/1032; Y10T117/1036; Y10T117/1044
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
87 words
A crystal growing apparatus for growing a crystal by preparing a crystal raw material melt in a crucible, bringing a seed crystal into contact with the melt and pulling the seed crystal, comprising: an electrode arranged above the melt at a distance therefrom, means for detecting a change in a resistance of an atmosphere between said electrode and the melt, and means for controlling a pulling speed of the crystal in accordance with a detection output from said detecting means, thereby controlling a dimension of the crystal.
Claim 2
Dependent Claim
87 words
A crystal growing apparatus for growing a crystal by preparing a crystal raw material melt in a crucible, bringing a seed crystal into contact with the melt and pulling the seed crystal, comprising: an electrode arranged above the melt at a distance therefrom, means for detecting a change in a resistance of an atmosphere between said electrode and the melt, and means for controlling a pulling speed of the crystal in accordance with a detection output from said detecting means, thereby controlling a dimension of the crystal.
Claim 3
Dependent Claim
23 words
An apparatus according to claim 1, wherein a distal end of said electrode which faces the melt consists of a p-type silicon carbide.
Claim 4
Dependent Claim
88 words
A crystal growing apparatus for growing a crystal by preparing a crystal raw material melt in a crucible, bringing a seed crystal into contact with the melt and pulling the seed crystal, comprising: an electrode arranged above the melt at a distance therefrom, means for detecting a change in a resistance of an atmosphere between said electrode and the melt, and means for controlling a power supply for heating the melt in accordance with a detection output from said detecting means, thereby controlling a dimension of the crystal.
Claim 5
Dependent Claim
88 words
A crystal growing apparatus for growing a crystal by preparing a crystal raw material melt in a crucible, bringing a seed crystal into contact with the melt and pulling the seed crystal, comprising: an electrode arranged above the melt at a distance therefrom, means for detecting a change in a resistance of an atmosphere between said electrode and the melt, and means for controlling a power supply for heating the melt in accordance with a detection output from said detecting means, thereby controlling a dimension of the crystal.
Claim 6
Dependent Claim
23 words
An apparatus according to claim 3 wherein a distal end of said electrode which faces the melt consists of a p-type silicon carbide.
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) | 1988-04-22 | 1988-10-22 | 1989-04-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-04-22 | 1992-10-22 | 1993-04-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-04-22 | 1996-10-22 | 1997-04-23 | $7700.00 | Window Closed / Lapsed |