Homoepitaxial GaN grown by metal organic chemical vapour deposition on the N-polar surface of bulk GaN commonly exhibits gross hexagonal pyramidal features, typically 5 to 50μm in size, depending on layer thickness. The evolution of these defects is dominated by the growth rate of an emergent core of inversion domain (typically 100nm in size). The associated nucleation events are considered to be thin bands of amorphous gallium hydroxide (2 to 5nm in thickness) remnant from the standard KOH chemo-mechanical substrate polishing procedure used.
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