Application of X-Ray Scattering to the in Situ Study of Organometallic Vapor Phase Epitaxy

ABSTRACTDespite their importance, the detailed surface reactions and rearrangements which occur during chemical vapor deposition remain largely undetermined because of the lack of suitable experimental probes. In principle, x-ray scattering and spectroscopy techniques are well suited to studying these near atmospheric pressure processes but advances in this area have been limited both by the lack of suitable x-ray sources and by the difficulty of integrating the growth and measurement experiments. We have developed equipment and techniques to perform in situ x-ray scattering studies of the structure of surfaces during organometallic vapor phase epitaxial (OMVPE) growth using the extremely bright undulator radiation from the PEP electron storage ring. In this paper, we describe our initial experimental results studying cleaning and subsequent reconstruction of GaAs (001) surfaces in a flowing H2 ambient. These results demonstrate the excellent surface sensitivity, low background and high signal levels necessary to study the dynamic processes associated with semiconductor growth using OMVPE.