Two Step Growth of InN Films on Sapphire (0001) Substrates Without Nitridation Process by RF-MBE

Abstract

InN films were grown on sapphire (0001) substrates by radio-frequency plasma-assisted molecular beam epitaxy. The InN buffer layers deposited at low temperature were either grown on a substrate with nitridation or on a substrate without nitridation. The InN buffer layers on the nitridated substrates were always single crystalline, whereas the buffer layers on non-nitridated substrates were always polycrystalline. However, even without nitridation process, single crystalline InN films could be grown on the polycrystalline InN buffer layers; in this case, the orientation was always [1120] InN//[1120] sapphire epitaxy, which differed from the [1010] InN//[1120] sapphire epitaxy in films grown with nitridation.

Growth of high-quality InN films by insertion of high-temperature InN buffer layer

“…Substrate nitridation also has an effect for the crystallinity of the LT-InN buffer layer. The buffer layer deposited without substrate nitridation is revealed to be mostly c-axis-oriented polycrystalline by the RHEED pattern [10]. For the buffer layer deposited after nitridation, on the other hand, the pattern always shows streaks [10,11], which indicate the presence of single crystals.…”

“…The buffer layer deposited without substrate nitridation is revealed to be mostly c-axis-oriented polycrystalline by the RHEED pattern [10]. For the buffer layer deposited after nitridation, on the other hand, the pattern always shows streaks [10,11], which indicate the presence of single crystals. In addition, the crystallinity of the InN film overgrown on the buffer layer without nitridation is always inferior to that of the film grown with nitridation.…”