Patent ID: 8110484
Filing Date: 2012-02-07
Classification: C30B,H01L

Abstract:
1. A method for producing a conductive nitride semiconductor substrate, comprising the steps of: preparing an underlying substrate having a c-plane or a plane with three-fold symmetry; forming, on the underlying substrate, masking portions having a width or diameter of 10 to 100 μm and periodically repeated at a spacing of 250 to 10,000 μm and an exposed portion where the substrate is exposed; growing a nitride semiconductor crystal having facets in a surface thereof on the underlying substrate by hydride vapor phase epitaxy (HVPE) at a crystal growth temperature of 1,040° C. to 1,150° C. while doping the nitride semiconductor crystal with silicon and oxygen by supplying a group III source gas, a group V source gas, a silicon compound gas, and water or oxygen in a V/III ratio of 1 to 10 so that low-dislocation-density single-crystal regions Z following the facets and a c-plane growth region Y following a flat face are formed above the exposed portion and crystal defect cluster regions H are formed above the masking portions, the nitride semiconductor crystal being doped with oxygen and silicon through the facets and with silicon through a c-plane and having an HZYZHZYZ . . . structure in an inner portion thereof; removing the underlying substrate; and polishing the surface of the nitride semiconductor crystal to form a free-standing conductive nitride semiconductor crystal having a cracking ratio K of 1%≦K≦22%.