Low temperature inorganic chemical vapor deposition of heteroepitaxial GaN

We have developed a highly efficient method of growing thin oriented films of GaN on basal plane sapphire and (100) Si substrates using an exclusively inorganic single-source precursor free of carbon and hydrogen. Cross sectional transmission electron microscopy of the highly conformal films revealed columnar material growth on Si and heteroepitaxial columnar growth of crystalline GaN on sapphire. Rutherford backscattering spectroscopy (RBS) of layers grown at 700°C confirmed stoichiometric GaN. Auger and RBS oxygen and carbon resonance profiles indicated that the films were pure and highly homogeneous. With respect to current chemical vapor deposition processes for GaN growth, our approach offers a number of potentially important improvements. These include high growth rates of 5-350 nm/min, low deposition temperature of 650-700°C, nearly ideal Ga-N stoichiometry, elimination of the highly inefficient use of toxic ammonia, and a carbon-hydrogen free growth environment that could prove to be beneficial to p-doping processes.