MOVPE high quality GaN film grown on Si (111) substrates using a multilayer AlN buffer

High quality GaN films were successfully grown on Si (111) substrates using the MOVPE method and a multilayer AlN buffer. The buffer layer film quality and thickness are critical for the growth of the crack-free GaN film on Si (111) substrates. Cracks started to form on the single layer high temperature (HT) AlN film, grown on Si (111) substrate as the AlN thickness was greater than 20 nm. However, a 100 nm crack-free AlN film, can be obtained when multilayer buffer of HT-AlN/low temperature (LT)-AlN/HT-AlN was grown on the Si(111) substrate. By using multilayer AlN buffer, a 2 mu m crack-free GaN film was successful grown on the 2 '' Si (111) substrate. Moreover, the GaN film (2 mu m thick) grown on Si with a GaN (004) Mosaic FWHM of only 0.12 degrees.