Defect reduction in nonpolar and semipolar GaN using scandium nitride interlayers

摘要

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 5 nm 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) × 10~9cm~(-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) × 10~8cm~(-2). Nonpolar film surface roughnesses were reduced by a factor of 20.