Dislocation reduction in GaN thin films via lateral overgrowth from trenches

Abstract

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 sidewalls to form a continuous thin film. The average surface density of threading dislocations is reduced from ${\text{8×10}}^9/{\mathrm{cm}}^{\mathrm{2}}$ in the first GaN thin film to ${\text{6×10}}^7/{\mathrm{cm}}^{\mathrm{2}}$ in the regrown GaN thin film.