Inversion domains and pinholes in GaN grown over Si(111)

High-resolution transmission electron microscopy is used to analyze the connection between pinholes and inversion domains at the AlN/GaN interface. From some pinholes on top of the AlN buffer layer, the subsequent growth of GaN was observed to lead to the formation of inversion domains. In addition, the pinhole area which was originally the termination of defects from the buffer layer is highly strained and its boundary facets in 112̄2 and 112̄3 atomic planes. Inside the GaN the inversion domain boundary quickly settles to the usual 101̄0 planes.