It was recalled that SiNx interlayers could act as anti-surfactants and drastically reduce the dislocation density in pure GaN layers. Here, very efficient annihilation of a-type threading dislocations was observed at a fractional SiNx monolayer, even in AlxGa1−xN layers with the relatively high Al content of x = 0.2, grown onto c-plane sapphire by MOVPE. The investigation focused upon the effect of the SiNx interlayer upon the density reduction of a-type threading dislocations. Direct weak-beam dark-field and high-resolution transmission electron microscopy of the SiNx interface indicated that the most frequently occurring effect in the reduction of a-type threading dislocations was conversion of an a-type threading dislocation into an a-type basal dislocation due to lateral overgrowth of SiNx by AlGaN.

Simulation Supported Analysis of the Effect of SiNx Interlayers in AlGaN on the Dislocation Density Reduction. O.Klein, J.Biskupek, U.Kaiser, K.Forghani, S.B.Thapa, F.Scholz: Journal of Physics - Conference Series, 2010, 209[1], 012018