Patent ID: 8845992
Filing Date: 2014-09-30
Classification: C30B

Abstract:
1. A method of manufacturing a III-nitride single-crystal ingot, characterized by including: a base-substrate preparation step of machining a III-nitride base substrate into one of either a round form or a hexagonal form in which the base substrate has planar major surfaces and is either round or hexagonal in cross-section of the base substrate perpendicular to its thickness dimension; a preprocess step of either vapor- or liquid-phase etching the edge surface of the III-nitride base substrate prepared in said base-substrate preparation step, so as to remove at least 1 μm of the base-substrate edge surface; and a step of growing, by vapor-phase epitaxy, directly onto one of the major surfaces and the edge surface of the preprocessed base substrate, hexagonal-system III-nitride monocrystal by means of precursor gases and oxygen-containing dopant gas under growth conditions predetermined such that the side surfaces of the epitaxially grown monocrystal are crystallographic planes, to form the monocrystal as a first region, containing the center of the monocrystal in a cross section perpendicular to its thickness dimension and extending along the thickness dimension, and a second region, containing the side surfaces of the monocrystal and located on the perimeter of the first region, and such that the first region has an oxygen-impurity concentration that is at least an order of magnitude lesser than that of the second region, whereby the monocrystal is essentially crack-free.