Dislocation reduction in GaN thin films via lateral overgrowth from trenches

A technology to reduce the dislocation density in GaN thin films by lateral overgrowth from trenches (LOFT) is reported. In LOFT, a GaN thin film was grown on sapphire substrate first, then trenches were formed into the thin film by etching. GaN material was regrown laterally from the trench sidewal ls to form a continuous thin film. The average surface density of threading dislocations is reduced from 8x10(9)/cm(2) in the first GaN thin film to 6 x10(7)/cm(2) in the regrown GaN thin film. (C) 1999 American Institute of P hysics. [S0003-6951(99)00840-2].