Patent US3829556A successfully refreshed from Google Patents.
US3829556A
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Growth of gallium nitride crystals
Assignee: AT&T Inc
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Filing: 1972-03-24
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Granted: 1974-08-13
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Expires: 1992-03-24
Abstract
Abstract The size and photoluminescent efficiency of crystals of gallium nitride, grown in a solution of molten gallium and bismuth, are improved by maintaining the partial pressure of ammonia vapor in a hydrogen gas atmosphere flowing above the solution at a value which is, at most, about an order of magnitude greater than the ''''equilibrium pressure'''' of formation vs. decomposition of gallium nitride. The photoluminescent efficiency of a blue band, whose energy is centered around 4,350 angstroms, emitted by such gallium nitride crystals is also improved by introducing zinc vapor into the carrier gas.
Inventors
- 👤 R Logan
- 👤 C Thurmond
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 08:22
CPC Classifications
C; C30; C30B; C30B29/00; C30B29/10; C30B29/40; C30B29/403; C30B29/406; C09; C09K; C09K11/00; C09K11/08; C09K11/74; C09K11/7492; C30B19/00; C30B19/02
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
41 words
The method recited in claim 1 in which the composition of the solution is in the range between about 10 atomic percent to about 90 atomic percent bismuth in gallium, and the partial pressure of ammonia vapor does not exceed 0.03.
Claim 2
Dependent Claim
36 words
The method recited in claim 1 in which a temperature gradient is established across the exposed surface of the solution, said temperature gradient being in the range of about 17* to about 33* C. per inch.
Claim 3
Dependent Claim
28 words
The method recited in claim 1 in which the said partial pressure of the ammonia vapor is no more than about five times the said equilibrium partial pressure.
Claim 4
Dependent Claim
20 words
The method recited in claim 4 in which the partial pressure of ammonia vapor is about twice the equilibrium pressure.
Claim 5
Dependent Claim
18 words
The method recited in claim 1 in which the substrate has a predeposit thereon of epitaxial gallium nitride.
Claim 6
Dependent Claim
16 words
The method recited in claim 1 which further includes introducing zinc vapor into the gas mixture.
Claim 7
Dependent Claim
21 words
The method recited in claim 7 in which the partial pressure of zinc vapor is of the order of 0.1 atmosphere.
Claim 8
Independent Claim
120 words
A method of growing a crystal of gallium nitride which comprises: a. placing a substrate of sapphire in a solution comprising molten gallium and an inhibitor of the growth of gallium nitride, at a temperature in the range of between about 850*C and about 1,050*C, said inhibitor being essentially a member of the group consisting of bismuth, antimony, tin, thallium and indium; b. flowing a gas mixture containing ammonia vapor in hydrogen across the exposed surface of the solution, said ammonia vapor being at a predetermined partial pressure no more than five times the equilibrium pressure for the formation vs. decomposition of gallium nitride, whereby a single crystal layer of gallium nitride is grown on the substrate in the solution.
Claim 9
Dependent Claim
38 words
The method of claim 9 in which a temperature gradient is maintained in the range of about 17* to about 33*C per inch across the exposed surface of the solution during the step of flowing the gas mixture.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-08-12 | 1978-02-11 | 1978-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-12 | 1982-02-11 | 1982-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-12 | 1986-02-11 | 1986-08-13 | $7700.00 | Window Closed / Lapsed |