Kinetics and growth mechanism of gallium arsenide crystals in gas-phase epitaxy

Abstract

In conclusion, we note that gallium arsenide itself is the material with which the physicochemical and crystallophysical fundamentals of gas-phase epitaxy are presently being developed. It is hoped that the basic principles or crystal growth in gas-phase systems discovered in gallium arsenide will prove sufficiently general to be applied to other analogous systems. The complex multistage processes occurring on a crystal surface during gas-phase crystallization require development of a more general theory of crystal growth — one which considers heterogeneous reactions and participation in the surface processes of noncrystallizing atoms and molecules. On the other hand, for construction of such a theory and its comparison to experiment information will be required not only on the composition of the gaseous phase and the growth kinetics, but also on the composition and structure of the adsorption layer and the crystallization surface, the acquisition of which in gas-phase systems is complicated in comparison to, for example, molecular-beam epitaxy systems. It is possible that these difficulties will be overcome with time. A certain part of the information on composition and structure of the surface in contact with the complex gas phase can apparently be obtained under conditions close to equilibrium. This part of the problem of gas-phase epitaxy research merges completely with problems of the characterization of the physicochemical state of semiconductor surfaces in general.