CTS-9500387 Robert Hicks A scanning tunnelling microscope (STM) is added to a system consisting of a reactor for vapor-phase expitaxy and a chamber for surface analysis. These are interfaced with an ultrahigh-vacuum server that allows transfer of samples among the three stations without exposure to air. The STM is to be used to study the surface structure of II-VI films, the atomic ordering of III-V alloys, the heteroepitaxy of compound semiconductors on silicon, and the molecular kinetics of III-V and II-VI organmetallic vapor-phase epitaxy (OMVPE).