Initial stages of the GaN growth on oxidized silicon

Abstract

Initial stages of the GaN layer growth during an HVPE process at 520°C on an oxidized silicon substrate were studied by atomic force microscopy. It was established that (i) the growth of GaN islands is controlled by the surface diffusion and (ii) the nucleus size distribution on the surface significantly changes when the growth time increases from 10 to 200 min: during this period of time, the average nucleus size increases from 15 to 400 nm and their size scatter becomes 20 times as large as the initial size distribution width. The experimentally determined growth rate of the GaN nuclei and the nucleus size distribution are in good agreement with theoretical calculations.