DYNAMICS AND KINETICS OF MBE GROWTH

The epitaxial growth of semiconductor films from molecular beams in an ultra-high-vacuum environment has made available structures of unprecedented complexity and precision. In parallel, the application of surface science techniques and computer simulation to studies of surface reaction kinetics and growth dynamics has allowed very significant advances to be made in our understanding of epitaxial film growth at the atomic level. The experimental techniques which have been used most extensively are modulated beam relaxation spectroscopy (MBRS) and reflection high energy electron diffraction (RHEED). A summary of results from solid sources for both lattice matched and strained layer systems which illustrate our present level of knowledge is related to Monte Carlo growth simulations and an analytical treatment of non-linear nucleation kinetics. Particular attention is focussed on cation effects in the growth of III-V compounds over a wide temperature range. In addition to MBRS and RHEED, optical methods such as reflectance difference spectroscopy and surface photo-absorption have recently been introduced as in-situ diagnostic probes to study surface chemistry and growth morphology. The information derived from this type of measurement is considered in the context of growth models developed from the longer-established techniques.