ORGANOMETALLIC PRECURSORS IN THE GROWTH OF EPITAXIAL THIN-FILMS OF GROUPS III-V SEMICONDUCTORS BY METAL ORGANIC-CHEMICAL VAPOR-DEPOSITION

Metal-organic chemical vapor deposition (MOCVD) can now be used routinely for the preparation of a wide variety of groups III-V semiconductor materials. Ga- and In-based binary (e.g., GaAs, InP), ternary (e.g., In(x)Ga(1-x)As), and quaternary (e.g., In(x)Ga(1-x)P(y)As(1-y) compounds may be prepared as epitaxial layers ranging in thickness from a few angstroms to several microns for device applications. However, an understanding of the chemistry involved in the gas phase and at growing surfaces during MOCVD is at a primitive level despite the progress of the past few years. In this account we shall review recent progress in the use of organometallic precursors for MOCVD. The purity of these starting materials will be considered in relation to the quality of resulting epitaxial layers. Reaction mechanisms involved in their decomposition and reactivity both in the gas phase and at substrate surfaces will be discussed. Carbon incorporation is comprehensively covered, and growth using alternative group III and group V precursors together with the decomposition reactivity of these reagents is reviewed. The prospects for chemists in this research field are excellent, and in our opinion they are essential to its further development and extension into hitherto unexplored territories.