Methods and structures for preparing single crystal silicon wafers for use as substrates for epitaxial growth of crack-free gallium nitride films and devices

This document describes the fabrication and use of ceramic stabilizing layer fabricated right on the product silicon wafer to facilitate its use as a substrate for fabrication of gallium nitride films. A ceramic layer is formed and then attached to a single crystal silicon substrate to form a composite silicon substrate that has coefficient of thermal expansion comparable with GaN. The composite silicon substrates prepared by this invention are uniquely suited for use as growth substrates for crack-free gallium nitride films, benefitting from compressive stresses produced by choosing a ceramic having a desired higher coefficient thermal expansion than those of silicon and gallium nitride.