The effect of substrate nitridation temperature and buffer design on the quality of GaN epitaxial films

Abstract

A key issue for the entire field of III-Nitride materials growth is the unavailability of high quality lattice matched substrates. The most commonly used growth substrate, sapphire, still imposes constraints on the GaN film quality due to the lattice mismatch and control of polarity between sapphire and GaN . Therefore, the first stage of growth conditions (i.e. nitridation, types of buffer layers, growth ratio, annealing condition of buffer layer and so on) determines the characteristics (i.e. polarity, quality, and surface morphologies) of the subsequent GaN epitaxial layers. .Therefore, it is necessary to optimize the interface with the substrate and growth condition of buffer growth for the subsequent GaN epitaxial layer. In this work, we present the control of quality of GaN epitaxial layers with different nitridation temperatures. We present the dramatically improved structural quality of GaN epitaxial layers by optimized nitridation conditions.