A new GaAs, GaP, and GaAsxP1−x vacuum deposition technique using arsine and phosphine gas

A new vacuum deposition process for depositing thin films of GaAs, GaP, and GaAsxP1−x is described. This process is similar to the standard molecular beam technique except that the arsenic and phosphorus are supplied from the decomposition of arsine and phosphine gas. The advantages of this process over the more conventional one-source and two-source molecular beam techniques are that the new gas-source process is more easily controlled and more reproducible and the deposition source materials are essentially inexhaustible, permitting a large number of samples to be coated during a single run. The process has been optimized for depositing polycrystalline films 800–1000-A thick with sheet resistivities exceeding 1013 Ω/square for use as a resistive sea for silicon-diode-array camera tube targets. Variations in the deposition parameters, such as gallium temperature, the ratio of gallium to arsenic or phosphorus flux incident on the substrates, deposition time, and substrate temperature, were made to determi...