CPC C30B 25/18 (2013.01) [C01B 21/0632 (2013.01); C30B 25/04 (2013.01); C30B 29/406 (2013.01)] | 18 Claims |
1. A free-standing group III metal nitride substrate comprising at least two crystals, each of the at least two crystals comprising:
a group III metal selected from gallium, aluminum, and indium, or combinations thereof, and nitrogen, wherein:
each of the at least two crystals having a wurtzite crystal structure comprises a first surface having a maximum dimension greater than 10 millimeters in a first direction and a maximum dimension greater than 4 millimeters in a second direction orthogonal to the first direction, an average concentration of threading dislocations between 102 cm−2 and 1×106 cm−2, an average concentration of stacking faults below 103 cm−1, a symmetric x-ray rocking curve full width at half maximum less than 200 arcsec,
the magnitudes of a crystallographic miscut of the first surfaces of each of the at least two crystals are equal, to within 0.5 degree,
the directions of crystallographic miscuts of the first surfaces of each of the at least two crystals are equal, to within 10 degrees,
each of the at least two crystals is bonded to a matrix member comprising polycrystalline GaN that is textured in a c-direction, and
a polar misorientation angle γ between a first surface of a first crystal of the at least two crystals and a first surface of a second crystal of the at least two crystals is greater than about 0.005 degrees and less than about 0.2 degrees and misorientation angles α and β are greater than about 0.01 degrees and less than about 1 degree.
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