Patent ID: 8012882
Filing Date: 2011-09-06
Classification: C30B

Abstract:
1. A method of minimizing bow H in an as-grown GaN substrate, the method comprising: a grinding step of mechanically grinding the as-grown GaN substrate to induce into at least either its front or its back side a damage layer in which the crystalline structure of the substrate is transformed, with a grit selected to smooth the ground side of the substrate yet leave the damage layer being of thickness sufficient to stretch the ground side so as to reduce the substrate bow H to be within +30 μm≧H≧−30 μm; and an etching step of either wet-etching or dry-etching the ground side of the substrate to remove enough of the controlled-thickness damage layer such as to further reduce the bow H to be within +30 μm≧H≧−20 μm.