Growth of GaN on Si(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 x 10(9) cm(-2) for edge dislocations and 1 x 10(9) cm(-2) for screw dislocations are achieved in GaN films of 1 mum thickness grown under optimal conditions. Reverse leakage is observed near some dislocations, although the majority of dislocations do not produce leakage.