Use of Tertiarybutylarsine in the OMVPE Growth of GaAs.

Epitaxial films of GaAs have been grown by organometallic vapor phase epitaxy using a new arsenic source, tertiarybutylarsine (TBAs). Growth was performed on (100) undoped and (100+2degrees -> 110>) Cr-doped GaAs substrates. Films with excellent surface morphology were obtained over a wide temperature range (600- 800C), and relatively strong free exciton emission was observed in the photoluminescence spectra. The electrical properties appear to be limited by donor impurities in the as-received TBAs source material. Hall measurements indicate carrier concentrations as low as 5x10 sup 15 cm(-3) and mobilities of mu sub 300 =4000 cm(2)/V.s. The layers are n-type for all values of V/III ratio investigated. These are equivalent or better than results obtained with trimethylarsenic. Comparison of the experimental data indicates that the TBAs growth characteristics are similar to arsine, and suggests that TBAs thermally decomposes to yield arsine during the growth process.