ABSTRACT
The origin of inversion domains has been analysed in GaN epilayers grown by molecular beam epitaxy on AlN buffered (111) Si substrates. A topological approach is used to explain the formation of inversion domains from Si surface steps. The III-N films are grown on various substrates due to the fact that there is no commercially available bulk GaN. The epitaxy of GaN on (Ill) Si has been considered as a challenge to obtain competitive devices. The ability to characterise defect structures in GaN grown over (Ill) Si substrates, and to correlate these to particular growth mechanisms is of particular importance. The formation of these defects has been previously determined in GaN layers grown on sapphire substrates. Using a simple geometrical approach, the chapter examines the origin of inversion domain boundaries by considering the misfit between GaN and Si along the growth direction, that is at substrate steps.
