Low-temperature growth of AlN on nearly lattice-matched MnO substrates

We have investigated low-temperature epitaxial growths of AlN on nearly lattice-matched MnO(1 1 1) with pulsed laser deposition (PLD). Coaxial impact collision ion scattering spectroscopy (CAICISS) analysis has revealed that the surface of MnO(1 1 1) just before the growth consists of both the Mn-plane and the O-plane with a coverage ratio of 1:1. We have confirmed that the epitaxial growth temperature for AlN on MnO can be reduced down to 400 °C by the use of PLD. The roughness of the AlN/MnO interface decreased from 1.3 to 2.1 nm by the reduction of the growth temperature, which is probably due to the suppression of the intermixing reactions at the interface. On the contrary, the surface morphology of the AlN films was degraded by the reduction of the growth temperature probably due to the stress buildup caused by the suppression of the interface reactions.