COMPARISON OF ALTERNATE AS-SOURCES TO ARSINE IN THE MOCVD GROWTH OF GAAS

We have investigated the use of methyl-, ethyl-, and butyl-based alkylarsine compounds as alternatives to arsine in the epitaxial growth of GaAs. These are all low vapor pressure liquids that can be handled more safely than arsine, which is stored as a high pressure gas. Films were deposited over a wide range of growth conditions (T//g equals 550-850 degree C, V/III equals 2-20) at atmospheric pressure in a horizontal MOCVD reactor. The quality of the films grown with the alkylarsine sources was limited by the presence of both carbon and donor impurities. Isotopic labeling studies using 50% enriched **1**3C-trimethylarsine provided direct evidence that the methyl groups from trimethylarsine were a major source of the carbon observed in the films. The effects of source purity and composition on the morphological, electrical and optical properties of the GaAs films will be presented.