9414657 Shealy The ability to combine lithography, etching and epitaxial deposition of advanced semi-conductor material systems will have a significant impact on the realization of complex integrated electronic and optoelectronic circuits. The selective synthesis of III-V compound semiconductors using UV laser radiation in a low pressure Organometallic Vapor Phase Epitaxial (OMPVE) deposition environment will be investigated. The availability of coherent tunable UV laser sources with sufficient power allows localized activation of the semiconductor surface in both etching and epitaxial growth modes of operation. The apparatus used to support these studies is equipped with HCl gas which allows photo-simulated selective etching to be combined with selective growth. Several mechanisms are responsible for photo-simulated selective etching and epitaxial growth depending on the type of laser source used and the reactants present on the substrate surface. Among these mechanisms, one must consider thermal processes, photo-induced decomposition of reactants, and photo-generated carriers near the growth surface which alter the reaction kinetics. The tunable deep UV laser source will allow various forms of excitations which will help identify the important processes resulting in high quality selectively grown materials. Several lithographic techniques will be pursued to realize fine line geometries including focused laser scanning, projection through masks and interference holography. Emphasis will be placed on synthesis techniques resulting in high quality semiconductor structures with sub-micron resolution in order to support the broadest range of applications in devices and circuits. ***
