Engineered base substrates for releasing iii-v epitaxy through spalling

A method of forming a semiconductor structure comprising:

• forming a release layer over a base substrate, wherein the release layer is in contact with a Group III nitride surface;
• forming a patterned release layer comprising at least one opening and a plurality of wing regions, wherein each wing region is oriented along a <1100> direction of the Group III nitride surface, and wherein the at least one opening exposes at least one portion of the Group III nitride surface;
• forming a semiconductor layer over the at least one portion of the Group III nitride surface and each wing region of the patterned release layer by lateral epitaxial overgrowth, wherein the semiconductor layer has a corrugated bottommost surface provided with a plurality of indentations, each of the indentations enclosing a respective one of wing regions;
• removing the wing regions to provide a plurality of cavities;
• forming one or more stressor layers over the semiconductor layer, wherein a tensile stress in the one or more stressor layers is configured to cause at least one fracture initiated in a lower portion of the semiconductor layer regions having the cavities;
• and
• removing at least a portion of the semiconductor layer from the base substrate at the at least one fracture.