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

摘要

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, benefiting from compressive stresses produced by choosing a ceramic having a desired higher coefficient thermal expansion than those of silicon and gallium nitride.

主权项

1. A method comprising
providing a single crystal silicon substrate,
wherein the silicon substrate comprises a first side and a second side; attaching a layer to the first side of the silicon substrate to form a composite substrate,
wherein the layer has coefficient of thermal expansion (CTE) higher than that of GaN,wherein the effective CTE of the composite substrate is higher than that of GaN so that a subsequently deposited GaN layer on the second side of the silicon substrate does not crack at room temperature,wherein attaching the layer comprises
applying a paste on the first side of the silicon substrate,sintering the paste to solidify the paste to form the layer.