Overgrowth of indium nitride thin films on aluminum nitride nucleated (00.1) sapphire by reactive magnetron sputtering

Abstract

The growth and properties of thin films of InN on (00.1) sapphire and (00.1) sapphire nucleated by a 400 Å layer of AlN have been found to be radically different. The unnucleated InN films exhibit a mixed morphology (largely textured with lesser amounts of epitaxial grains), a monofunctional thickness dependence on sputtering time, uniformly low mobility and carrier concentration, and high resistivity. In contrast, the AlN-nucleated overlayers show only heteroepitaxial grains, a bifunctional dependence for the film thickness and surface roughness on sputtering time, higher mobility and carrier concentration, and lower resistivity−even in the limit of an InN overlayer on the order of 20–40 Å.