A composite substrate includes a single crystal silicon layer on a glass or glass ceramic layer on a support layer can be used to form GaN layer without cracks. The glass or glass ceramic layer can have a set point and/or strain point below the deposition temperature of GaN, which can assist in releasing stress in the deposited GaN layer. Additionally, the composite substrate can be exposed to a heated and dry hydrogen ambient to reduce an oxide layer between the silicon layer and the glass or glass ceramic layer, to allow the formation of free standing GaN layer.