Photo-assisted growth of gallium arsenide

Abstract Patterned GaAs layers have been deposited at temperatures from 25 to 400°C using a photochemically-assisted MOVPE technique. Low temperature layers showed an amorphous structure, but those deposited at 350°C were polycrystalline. Layers up to 2000 A thick were grown at a rate of 4000 A h -1 . XPS analysis indicated that stoichiometry varied with III–V precursor ratio, the optimum being approximately 3.3TMG: AsH 3 , with little evidence of background deposition in unilluminated areas, although some particulates due to gas phase decomposition were detected. At 400°C, gas phase decomposition becomes a major problem leading to loss of pattern definition.