Influence of the AlN buffer layer growth on AlGaN/GaN films deposited on (111)Si substrates

Use of an AlN buffer layer is an enabling technique for the epitaxial growth of GaN on Si(111) substrates. The AlN growth temperature has been shown to be a significant factor that affects the properties of the GaN film and the AlGaN/GaN heterostructure. The AlN buffer grown at 1155°C exhibited a uniform sized, preferred-oriented and highly faceted grain microstructure that led to subsequently grown AlGaN/GaN films with better quality than those on the AlN buffer grown at other temperatures. The AlGaN/GaN film quality evaluated included photoluminescence properties, surface planarity, Hall mobility and film strain