Organometallic vapor phase epitaxy (OMVPE)

Organometallic vapor phase epitaxy (OMVPE) has emerged in this past decade as a flexible and powerful epitaxial materials synthesis technology for a w ide range of compound-semiconductor materials and devices. Despite its capa bilities and rapidly growing importance, OMVPE is far from being well under stood: it is exceedingly complex, involving the chemically reacting flow of mixtures of organometallic, hydride and carrier-gas precursors. Recently, however, OMVPE technologies based on high-speed rotating disk reactors (RDR s) have become increasingly common. As fluid flow in these reactors is typi cally cylindrically symmetric and laminar, its effect on the overall epitax ial growth process is beginning to be unraveled through quantitative comput er models. In addition, over the past several years, a combination of well- controlled surface science and RDR-based growth-rate measurements has led t o a richer understanding of some of the critical gas and surface chemistry mechanisms underlying OMVPE. As a consequence, it is becoming increasingly possible to develop a quantitative and physically based understanding of OM VPE in particular chemical systems. In this article, we review this underst anding for the important specific case of AlGaAs OMVPE in an RDR under cond itions used for growing typical device heterostructures. Our goal is to use typical growth conditions as a starting point for a discussion of fundamen tal physical and chemical phenomena, beginning with the fluid flow through an RDR and ending with the chemical reactions on the surface. By focusing o n one particularly important yet relatively simple specific case, this revi ew differs from more comprehensive previous reviews. Viewed as a case study , though, it complements these previous reviews by illustrating the wide di versity of research that is related to OMVPE. It can also serve as a good s tarting point for the development and transfer of insights into other more complex cases, such as: OMVPE of materials families containing Sb, P or N s pecies, of other devices types, and in other more complex reactor geometrie s. (C) 1999 Elsevier Science S.A. All rights reserved.