Thin semiconductor films prepared by low pressure reactive deposition processes

Proc. Fifth Int. Conf. Metallurgical Coatings, San Francisco, Apr. 1978. See Met. A., 7910-72 0305. Ge and InP semiconductor epitaxial films with unintentional doping concentrations in the 1017 cm-3 range and electron mobilities > 100 cm2V-1 sec-1 deposited by alternative low pressure deposition processes. In both processes the semiconductors were formed by decomposing reactant gases in a chemical vapour deposition subchamber located within vacuum chamber and reaction byproducts were removed with a turbomolecular pump. For Ge films, was decomposed on a heated substrate, giving H2 gas as a byproduct. Gas phase reactants were used to achieve doping. InP films were deposited by evaporating In metal from an In source cavity into which mixture was introduced. The PH3 gas decomposed in the cavity and In vapour, P2 vapour, and H2 gas were emitted. In vapour pressure controlled film growth rate and stoichiometric films were produced by adjusting the PH3--H2 inlet to allow excess P2 vapour in inner growth chamber.--E.J.S.