Heteroepitaxy of GaN on Si(111) realized with a coincident-interface AlN/β-Si3N4(0001) double-buffer structure

Abstract

We present a stacked buffer mechanism for heteroepitaxial growth with large lattice mismatch. The stacked buffer consists of constituent layers, which can form coincident lattices at layer/layer and layer/substrate interfaces. For the case of GaN-on-Si(111) heteroepitaxy, we utilize the 1:2 and 5:2 coincident lattices formed at the β-Si3N4(0001)/Si(111) and AlN(0001)/β-Si3N4(0001) interfaces, respectively, to facilitate the double-buffer layer for GaN-on-Si heteroepitaxial growth. By using this buffer technique, we resolve the issue of autodoping resulting from Si outdiffusion when grown with a single AlN(0001) buffer. As a result, the epitaxial quality of GaN film is also significantly improved.