Purity and Purification of Source Materials for III-V MOCVD

The major factors that affect the quality of MOCVD-grown III-V electronic materials are reviewed. Of prime importance is the purity of the source compounds, for example, trimethylgallium (TMG), trimethylindium (TMI), arsine and phosphine. Generally, we find that the quality of these commonly used, commercially available sources are good, as evidenced by the relatively good electronic quality of the product compounds, GaAs and InP. Newer or less commonly used sources such as cyclopentadienylmagnesium (Cp₂Mg) or diethylarsine, may still require further purification. A simple apparatus for the laboratory-scale vacuum distillation of MOCVD source materials is presented. The utility and efficacy of this purification technique is demonstrated by its application to the purification of silicon- and oxygen-contaminated trimethylindium.