LAYER-BY-LAYER EPITAXIAL-GROWTH OF GAN AT LOW-TEMPERATURES

GaN films have been grown on (0001)Si SiC substrates from triethylgallium and ammonia sources using a self-terminating atomic layer epitaxy method, as well as a layer-by-layer technique and a novel reactor design employing hot filaments to decompose the ammonia. The material properties and growth process were strongly dependent on the temperature and exposure time. GaN grew in a self-terminating fashion for temperatures below 120-degrees-C but the films were amorphous. Above this temperature, the films were deposited in a layer-by-layer process giving single-crystal material in the 250-350-degrees-C range. Characterization of the films was conducted using reflection high energy electron diffraction, single-crystal X-ray diffraction, ellipsometry and high resolution transmission electron microscopy.