Preparation of Epitaxial GaAs and GaP Films by Vapor Phase Reaction

Single crystal films of GaAs and GaP have been grown from the vapor phase on several substrates in a closed system containing source material and hydrogen chloride. The GaAs and GaP source material reacts with HCl to form gallium chlorides and elemental arsenic or phosphorus. These are transported along a temperature gradient in the ampoule and deposited at the cooler end as GaAs or GaP , several hundred degrees below their melting points. Epitaxial GaAs films have been grown on monocrystalline Ge and GaAs substrates of various crystallographic orientations and GaP epitaxial films on GaAs and GaP . The conductivity type of the films was controlled by appropriate doping of the source material. The growth rates were determined as a function of temperature and intial HCl pressure.