Epitaxial growth of high-quality AlN films on metallic nickel substrates by pulsed laser deposition

Abstract

Single-crystalline AlN films have been grown on metallic nickel (Ni) substrates by pulsed laser deposition with an in-plane epitaxial relationship of AlN[110]//Ni[10]. The as-grown AlN films reveal that a very smooth AlN film surface with a root-mean-square roughness of 1.0 nm has been obtained, and there is no interfacial layer existing between the AlN films and the Ni (111) substrates. Furthermore, with the increase in the growth temperature, the surface morphologies, crystalline qualities, and interfacial properties of as-grown AlN films gradually deteriorate. The as-grown about 300 nm-thick AlN films are almost fully relaxed only with an in-plane compressive strain of 0.67%. This work has potential in applications of AlN-based devices which require abrupt hetero-interfaces and flat films surfaces.