Defect reduction in nonpolar and semipolar GaN using scandium nitride interlayers

Abstract

Nonpolar (112¯0) and semipolar (112¯2) GaN films were grown on sapphire by metalorganic vapour phase epitaxy using ScN interlayers of varying thicknesses. A 5nm interlayer reduced basal plane stacking fault (BSF) densities in nonpolar films by a factor of 2 and threading dislocation (TD) densities by a factor of 100 to (1.8±0.2)×109cm−2. An 8.5nm interlayer reduced BSF densities in semipolar films by a factor of 5 and reduced TD densities by a factor of 200 to (1.5±0.3)×108cm−2. Nonpolar film surface roughnesses were reduced by a factor of 20.