Microstructure and Interfaces of Ultra-Thin Epitaxial AlN Films Grown by Plasma-Enhanced Atomic Layer Deposition at Relatively Low Temperatures

We demonstrate the growth of ultra-thin AlN films on Si (111) and a GaN/sapphire (0001) substrate using atomic layer epitaxy in temperature range 360 to 420 °C. Transmission electron microscopy X-ray diffraction were used characterize interfaces, fine scale microstructure, crystalline quality thin films. Films deposited epitaxily with hexagonal structure, while substrate, film is epitaxial has been metastable zinc-blende cubic phase. reveals that interface not sharp, containing an intermixing AlN. show particularly strain, plays major role dictating crystal structure The estimated observed orientation relation, significantly lower for GaN as compared GaN. On other hand, strain relation 0.8% AlN, which substantially than Si(111).