Inventors:
Bing Han - Lansdale PA, US
Jonathan H. Tao - Oceanside CA, US
Madis Raukas - Charlestown MA, US
Keith A. Klinedinst - Hudson MA, US
Jan B. Talbot - San Diego CA, US
Kailash A. Mishra - North Chelmsford MA, US
Assignee:
OSRAM SYLVANIA Inc. - Danvers MA
The Regents of the University of California - La Jolla CA
International Classification:
C01F 17/00
C01B 21/072
C23C 8/24
C30B 11/00
C30B 9/00
C30B 19/00
H01B 1/02
US Classification:
423263, 423412, 148 166, 148317, 117 11, 117 73, 117 54, 2525181
Abstract:
Rare earth-activated aluminum nitride powders are made using a solution-based approach to form a mixed hydroxide of aluminum and a rare earth metal, the mixed hydroxide is then converted into an ammonium metal fluoride, preferably a rare earth-substituted ammonium aluminum hexafluoride ((NH)AlREF), and finally the rare earth-activated aluminum nitride is formed by ammonolysis of the ammonium metal fluoride at a high temperature. The use of a fluoride precursor in this process avoids sources of oxygen during the final ammonolysis step which is a major source of defects in the powder synthesis of nitrides. Also, because the aluminum nitride is formed from a mixed hydroxide co-precipitate, the distribution of the dopants in the powder is substantially homogeneous in each particle.