CHARACTERISTICS OF GASB GROWTH USING VARIOUS GALLIUM AND ANTIMONY PRECURSORS

We report the epitaxial growth of GaSb using trimethylgallium (TMGa) o r triethylgallium (TEGa) with trimethylantimony (TMSb), triethylantimo ny (TESb), or trisdimethylaminoantimony (TDMASb) in a low-pressure ver tical rotating-disk reactor. Growth is kinetically limited for TMGa in the temperature range 560 to 640 degrees C, and is mass-transport lim ited for TEGa in the range 525 to 640 degrees C. A minimum V/III ratio is necessary to obtain stoichiometric GaSb, and is dependent on the p yrolysis temperature of Ga and Sb precursors. Featureless morphology i s achieved for layers grown with TMGa or TEGa and TMSb, while surface defects are observed for layers grown with TEGa and TESb or TDMASb. Th ese observations are consistent with Fourier transform infrared measur ements, which indicate interactions between TEGa and TESb or TDMASb. A ll nominally undoped layers are p-type, with overall superior properti es being obtained for layers grown with TEGa and TMSb. However, growth conditions that yield layers with the best electrical properties do n ot necessarily correspond to the same conditions for highest optical q uality.