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 heteroepitaxialgrowth 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- Si 3 N 4 (0001)/ Si (111) and AlN (0001)/β- Si 3 N 4 (0001) interfaces, respectively, to facilitate the double-buffer layer for GaN-on-Si heteroepitaxialgrowth. 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 GaNfilm is also significantly improved.