Patent ID: 6890791

Claim:
A method of fabricating a semiconductor substrate for a com-pound semiconductor device, comprising: (a) providing a baseplate of a substance that permits epitaxial growth of compound semiconductors thereon; (b) creating a buffer region by causing a first compound semiconductor to grow epitaxially on the baseplate, the buffer region possibly containing dislocations; (c) creating a dislocation refracting region on a major surface of the buffer region by causing a second compound semiconductor, different from the first compound semiconductor, to grow epitaxially on the major surface of the buffer region, the dislocation refracting region having a major surface with a multiplicity of protuberances capable of refracting extensions of the dislocations from the buffer region; and (d) creating a leveling region on the major surface of the dislocation refracting region by causing a third compound semiconductor, different from the second compound semiconductor, to grow epitaxially on the major surface of the dislocation refracting region, the leveling region having a major surface of greater levelness than the major surface of the dislocation refracting region; (e) whereby the leveling region is less in dislocation density than the buffer region and the dislocation refracting region as the dislocations created in the buffer region are refracted away from the leveling region by the protuberances on the major surface of the dislocation refracting region.