Alternative Chemistries for Mocvd Growth of III/V Materials

Abstract

ABSTRACTAlkyl substituted arsine compounds, RnAsH3–α are attractive alternatives to arsine, AsH3. for metalorganic chemical vapor deposition (MOCVD) of GaAs-based compounds because they are typically low vapor pressure liquids which can be stored and handled more safely than the high-pressure gas cylinders used for AsH3. Despite their increased safety, the alkylarsines have not been widely used due to carbon incorporation problems and high background doping levels in the deposited films. To determine the impact of alternative growth chemistries on MOCVD processes we have investigated the thermochemistry controlling the decomposition of AsH3 and its alkyl substitutes. Data are presented on the thermal stability of the Ascompounds, their resulting growth properties, and the composition and formation kinetics of the volatile products formed during thermal decomposition in an H2 ambient. The gas phase reactions controlling decomposition are identified. The implications of our results for CVD growth models and the potential of alkylarsine compounds for different CVD processes are discussed.