Patent ID: 6849474

Claim:
A method for growing a gallium nitride based semiconductor material overlying a substrate of a dissimilar material, comprising: forming a first gallium nitride based semiconductor layer overlying said substrate, said first gallium nitride based semiconductor layer having defects due to a lattice mis-match between said substrate and said first gallium nitride based semiconductor layer; forming a trench in said first gallium nitride based semiconductor layer, said trench having a bottom surface and side walls; depositing a first material on a surface of said first gallium nitride based semiconductor layer to prevent a second gallium nitride based semiconductor layer from nucleating on said surface of said first gallium nitride based semiconductor layer; and growing said second gallium nitride based semiconductor layer, of a material different from said first gallium nitride based semiconductor layer, extending tom at least one of said side walls, a bottom surface of said trench being of a material such that said second gallium nitride based semiconductor layer will not nucleate thereon, said second gallium nitride based semiconductor layer having fewer defects than said first gallium nitride based semiconductor layer.