US4050905A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Growth of doped crystals
Assignee: Solon Technologies Inc
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Filing: 1975-05-27
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Granted: 1977-09-27
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Expires: 1995-05-27
Abstract
Abstract Large, doped crystal ingots are grown in a Stockbarger furnace from a melt of an alkali metal or alkaline earth metal salt using very slow oscillation (1 - 2 cycles per minute) of the ingot through a small arc of 5° -20° to produce an ingot having a more even distribution of dopant and an absence of open boundaries between macrocrystals within the ingot.
Inventors
- 👤 Carl F. Swinehart
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:47
CPC Classifications
C; C30; C30B; C30B11/00; C30B11/006; C30B29/00; C30B29/10; C30B29/12
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
101 words
In the Stockbarger method of growing inorganic alkali metal or alkaline earth metal salt crystal ingots of at least two inches in diameter and containing a plurality of crystal domains or macrocrystal components, from a stratified melt of the same containing up to 1.5% of a dissolved dopant, the improvement comprising slowly moving, with variable velocity, the solidified crystal with respect to the melt about a vertical axis at a rate that is adequate to maintain an even distribution of the dopant in the melt at the interface, but that is not sufficient to disturb the temperature gradient in the melt.
Claim 2
Dependent Claim
101 words
In the Stockbarger method of growing inorganic alkali metal or alkaline earth metal salt crystal ingots of at least two inches in diameter and containing a plurality of crystal domains or macrocrystal components, from a stratified melt of the same containing up to 1.5% of a dissolved dopant, the improvement comprising slowly moving, with variable velocity, the solidified crystal with respect to the melt about a vertical axis at a rate that is adequate to maintain an even distribution of the dopant in the melt at the interface, but that is not sufficient to disturb the temperature gradient in the melt.
Claim 3
Dependent Claim
13 words
The method of claim 1 wherein the relative movement is achieved by oscillation.
Claim 4
Dependent Claim
32 words
The method of claim 2 wherein the solidified crystal is oscillated at a frequency of between 1 and 2 cycles per minute through an arc of between about 5° and about 20°.
Claim 5
Dependent Claim
23 words
The method of claim 1 wherein the crystal has a rejection ratio with respect to the dopant of at least 3 to 1.
Claim 6
Dependent Claim
27 words
The method of claim 4 wherein the crystal is moved at a rate that is adequate to achieve laminar flow of the melt at the solid-liquid interface.
Claim 7
Dependent Claim
40 words
The method of claim 1 wherein the solidified crystal is rotated at a rate of between about 5° and 20° of arc per minute, said rotation being subject to a change of velocity at least once every 20° of rotation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-09-26 | 1981-03-28 | 1981-09-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-09-26 | 1985-03-28 | 1985-09-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-09-26 | 1989-03-28 | 1989-09-27 | $7700.00 | Window Closed / Lapsed |