Crystallinity and microstructures of aluminum nitride films deposited on Si(111) substrates

Abstract

The crystallinity and microstructures of MOCVD AlN films deposited on Si(111) substrates with and without a buffer layer(s) were determined. The buffer layers were a thin 3C–SiC(111) layer produced via conversion of a Si(111) surface and a film stack consisting of graded-Al x Ga 1− x N/GaN/3C–SiC. A randomly oriented polycrystalline AlN film was obtained when this material was deposited directly on the Si(111). The use of a buffer layer led to the growth and coalescence of highly oriented AlN films produced by the coalescence of grains having average misalignments along the c-axis of 1.8° and that on the c-plane of 3.3°. The grains exhibited strongly faceted tips. The 2H–AlN(0001) films grown on a 3C–SiC(111) buffer layers showed adequate crystal perfection for use as a template for growth of single-crystal GaN and/or Al x Ga 1− x N films.