US4767607A
Expired / Lapsed
US
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Method for production of high purity aluminum nitrides
Assignee: POLYTECHNIC UNIVERSITY 333 JAY STREET BROOKLYN NEW YORK 11201
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Filing: 1987-09-02
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Granted: 1988-08-30
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Expires: 2007-09-02
Abstract
Abstract An efficient, low-temperature process for the preparation of highly pure, free-flowing aluminum nitride powder without oxygen contamination, comprising the steps of: (1) forming a mixture of ##STR1## and (b) AlCl 3 ; (2) reacting the mixture formed in step (1) at a temperature of from 0° C. to 150° C. and thereby forming ##STR2## (3) maintaining the Cl 2 --Al--NH--Si(CH 3 ) 3 formed in step (2) at a temperature of from 170° C. to 200° C. and thereby forming Cl--Al--NH and (CH 3 ) 3 --SiCl; and (4) maintaining the Cl--Al--NH formed in step (3) at a temperature of at least 450° C. and thereby forming H 2 , Cl 2 , and AlN.
Inventors
- 👤 Donald M. Schleich
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:34
CPC Classifications
C; C01; C01B; C01B21/00; C01B21/06; C01B21/072; C01P; C01P2002/00; C01P2002/80; C01P2002/82; C01P2006/00; C01P2006/12; C01P2006/60
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
134 words
A method for the preparation of aluminum nitride comprising the steps of: (1) forming a mixture of ##STR8## where R 1 and R 2 are each alkyl groups containing 1 to 4 carbon atoms, and (b) AlCl 3 ; (2) reacting the mixture formed in step (1) at a temperature of from 0° C. to 150° C. and thereby forming a mixture of Cl 2 --Al--NH--Si--(R 1 ) 3 , Cl 2 --Al--NH--Si--(R 2 ) 3 , (R 1 ) 3 --Si--Cl, and (R 2 ) 3 --Si--Cl; (3) converting the compounds formed in step (2) at elevated temperatures to (R 1 ) 3 --Si--Cl, (R 2 ) 3 --Si--Cl, H 2 , Cl 2 , and AlN; and (4) separating the H 2 , Cl 2 , and AlN from the mixture converted.
Claim 2
Independent Claim
134 words
A method for the preparation of aluminum nitride comprising the steps of: (1) forming a mixture of ##STR8## where R 1 and R 2 are each alkyl groups containing 1 to 4 carbon atoms, and (b) AlCl 3 ; (2) reacting the mixture formed in step (1) at a temperature of from 0° C. to 150° C. and thereby forming a mixture of Cl 2 --Al--NH--Si--(R 1 ) 3 , Cl 2 --Al--NH--Si--(R 2 ) 3 , (R 1 ) 3 --Si--Cl, and (R 2 ) 3 --Si--Cl; (3) converting the compounds formed in step (2) at elevated temperatures to (R 1 ) 3 --Si--Cl, (R 2 ) 3 --Si--Cl, H 2 , Cl 2 , and AlN; and (4) separating the H 2 , Cl 2 , and AlN from the mixture converted.
Claim 3
Independent Claim
101 words
A method for the preparation of aluminum nitride comprising the steps of: (1) forming a mixture of ##STR9## and (b) AlCl 3 ; (2) reacting the mixture formed in step (1) at a temperature of from 0° C. to 150° C. and thereby forming ##STR10## (3) maintaining the ##STR11## formed in step (2) at a temperature of from 170° C. to 200° C. and thereby forming Cl--Al--NH and (CH 3 ) 3 --SiCl; and (4) maintaining the Cl--Al--NH formed in step (3) at a temperature of at least 450° C. and thereby forming H 2 , Cl 2 , and AlN.
Claim 4
Independent Claim
101 words
A method for the preparation of aluminum nitride comprising the steps of: (1) forming a mixture of ##STR9## and (b) AlCl 3 ; (2) reacting the mixture formed in step (1) at a temperature of from 0° C. to 150° C. and thereby forming ##STR10## (3) maintaining the ##STR11## formed in step (2) at a temperature of from 170° C. to 200° C. and thereby forming Cl--Al--NH and (CH 3 ) 3 --SiCl; and (4) maintaining the Cl--Al--NH formed in step (3) at a temperature of at least 450° C. and thereby forming H 2 , Cl 2 , and AlN.
Claim 5
Dependent Claim
34 words
A method as recited in claim 2 wherein the mixture formed in step (1) is reacted at a temperature of 0° C. to 150° C. for a period of from 0.5 to 5 hours.
Claim 6
Dependent Claim
39 words
A method as recited in claim 2 wherein the Cl 2 --Al--NH--Si(CH 3 ) 3 formed in step (2) is a fine powder and said powder is separated from the (CH 3 ) 3 --Si--Cl formed in step (2).
Claim 7
Dependent Claim
36 words
A method as recited in claim 4 wherein the Cl 2 --Al--NH--Si(CH 3 ) 3 powder is maintained at a temperature of from 170° to 200° C. to form Cl--Al--NH and (CH 3 ) 3 --Si--Cl.
Claim 8
Dependent Claim
31 words
A method as recited in claim 5 wherein the Cl--Al--NH formed is a fine powder and said powder is separated from the (CH 3 ) 3 --Si--Cl found in claim 2.
Claim 9
Dependent Claim
39 words
A method as recited in claim 6 wherein the Cl--Al--NH powder is maintained at a temperature above 450° C. for at least 1 hour and at a temperature above 700° C. for at least 1 hour to form AlN.
Claim 10
Dependent Claim
41 words
A method as recited in claim 2 wherein the mixture formed in step (1) includes a solvent selected from the group consisting of methylene chloride, carbon disulfide, dichloroethane, and any other solvent which dissolves AlCl 3 and silazane without chemical reaction.
Claim 11
Dependent Claim
51 words
A method as recited in claim 2 wherein one or both of the Cl 2 --Al--NH--Si(CH 3 ) 3 formed in step (2) and the Cl--Al--NH found in step (3) are maintained at elevated temperatures in the presence of an active gas selected from the group consisting of ammonia or hydrogen.
Claim 12
Independent Claim
103 words
A method for the preparation of aluminum nitride comprising the steps of: (1) forming a mixture of (a) ##STR12## and (b) AlCl 3 ; (2) reacting the mixture formed in step (1) at a temperature of from 60° C. to 150° C. and thereby forming ##STR13## (3) maintaining the Cl 2 --Al--N--[Si(CH 3 ) 3 ] 2 formed in step (2) at a temperature of from 170° C. to 200° C. and thereby forming 2(CH 3 ) 3 --SiCl and amorphous AlN; and (4) heating the AlN formed in step (3) to at least 700° C. to transform the material to crystalline AlN.
Claim 13
Independent Claim
103 words
A method for the preparation of aluminum nitride comprising the steps of: (1) forming a mixture of (a) ##STR12## and (b) AlCl 3 ; (2) reacting the mixture formed in step (1) at a temperature of from 60° C. to 150° C. and thereby forming ##STR13## (3) maintaining the Cl 2 --Al--N--[Si(CH 3 ) 3 ] 2 formed in step (2) at a temperature of from 170° C. to 200° C. and thereby forming 2(CH 3 ) 3 --SiCl and amorphous AlN; and (4) heating the AlN formed in step (3) to at least 700° C. to transform the material to crystalline AlN.
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) | 1991-08-30 | 1992-02-29 | 1992-08-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-08-30 | 1996-02-29 | 1996-08-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-08-30 | 2000-02-29 | 2000-08-30 | $7700.00 | Window Closed / Lapsed |