Defect reduction in nonpolar and semipolar GaN using scandium nitride interlayers
Moram, M A and Johnston, C F and Kappers, M J and Humphreys, C J
Nonpolar (1 1 -2 0) and semipolar (1 1 -2 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\^9 cm−2. An 8.5 nm 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\^8 cm−2. Nonpolar film surface roughnesses were reduced by a factor of 20.
Department of Materials
Imperial College London
Royal School of Mines
London, SW7 2AZ - UK