Method and apparatus for producing large, single-crystals of aluminum nitride
First Claim
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1. An aluminum nitride single-crystal boule having a diameter greater than about 25 mm, a surface substantially all of which has a single crystalline orientation, and an average dislocation density less than about 10,000 cm−
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Abstract
Bulk single crystals of AlN having a diameter greater than about 25 mm and dislocation densities of about 10,000 cm−2 or less and high-quality AlN substrates having surfaces of any desired crystallographic orientation fabricated from these bulk crystals.
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Citations
20 Claims
- 1. An aluminum nitride single-crystal boule having a diameter greater than about 25 mm, a surface substantially all of which has a single crystalline orientation, and an average dislocation density less than about 10,000 cm−
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10. A method of producing single-crystal AlN, the method comprising:
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providing Al and N2 vapor in a crystal growth enclosure; providing a nucleation site in the crystal growth enclosure; maintaining in the crystal growth enclosure (i) an N2 partial pressure greater than stoichiometric pressure relative to the Al, (ii) a total vapor pressure at super-atmospheric pressure, (iii) an axial thermal gradient along a growth direction, and (iv) a lateral thermal gradient (a) along a direction substantially perpendicular to the growth direction and (b) in which a temperature at the nucleation site is lower than that in a region laterally displaced therefrom; and depositing the Al and N2 vapor under conditions capable of growing single crystalline AlN originating at the nucleation site. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification