Growth of GaN on SiC(0001) by Molecular Beam Epitaxy

GaN films are grown by plasma-assisted molecular beam epitaxy on 6H-SiC(0001) substrates. Suitable substrate preparation and growth conditions are found which greatly improve the structural quality of the films. Threading dislocation densities of about 1 × 10⁹ cm^—2 for edge dislocations and 1 × 10⁷ cm^—2 for screw dislocations are achieved in GaN films of 1 μm thickness grown under optimal conditions. Reverse leakage is observed near some dislocations, although the majority of dislocations do not produce leakage.