Mass spectroscopic study of photolytically driven deposition of gallium arsenide

The authors describe results on the use of ultraviolet radiation to deposit GaAs thin films at substrate temperatures less than those necessary for the deposition of GaAs using pyrolytic means. A 1000-W Hg-Xe arc lamp is utilized to achieve deposition, with arsine and triethylgallium serving as reactants. Deposition is carried out in a low-pressure chemical vapor deposition system at a pressure of 2 Torr. It is shown that, at least for the case where the light beam is incident perpendicular to the substrate, single-crystal epitaxial GaAs films can be obtained. Further, a mass spectroscopic study of the photolytic decomposition of triethylgallium indicates that the photolytic cracking of the molecule proceeds in a manner very similar to that found in thermal decomposition