Crystallographic Orientation and Surface Morphology of Chemical Vapor Deposited Al2 O 3

Abstract

Deposits of aluminum oxides have been formed by a chemical vapor deposition technique involving the application of gaseous mixtures of , , and onto cemented carbide substrates. Reaction parameters (deposition temperature, system pressure, and composition of reactant gases) and their effects on the crystalline structure, crystallographic orientation, and surface morphology of the deposit have been studied. crystals maintain a corundum structure throughout the entire range of deposition conditions. Crystals of appear to nucleate in random orientations on the layer, and further growth proceeds with (104) and (116) preferred orientations. The effects of reaction parameters on the final surface morphology of the deposit can be described by considering the supersaturations of the reactants and the growth rate. The crystals of the deposit become finer and more uniform as the supersaturation of the reactant controlling the nucleation increases.