An evaluation of alternative precursors in chemical beam epitaxy: tris-dimethylaminoarsenic, tris-dimethylaminophosphorus, and tertiarybutylphosphine

In this paper we evaluate the use of tris-dimethylaminoarsenic (TDMAAs), tris-dimethylaminophosphorus (TDMAP), and tertiarybutylphosphine (TBP) as safer alternative sources in CBE. TDMAAs is a viable alternative to arsine for growing GaAs. When In-containing compounds were grown using uncracked TDMAAs or TDMAP with trimethylindium, indium-enhanced TDMAP or TDMAAs desorption was observed, resulting in In droplets on the surface. InP can be grown only if TDMAP is cracked, but many surface defects are observed and the growth rate is very sensitive to the growth temperature. When TBP is used, however, a specular surface can be achieved, and the InP growth rate is independent of substrate temperature from 440 to 480 degrees C. TDMAAs and TDMAP are found to etch GaAs, InP, and GaP, which shows potential applications in in-situ etching and regrowth.