Triisopropylantimony for organometallic vapor phase epitaxial growth of GaSb and InSb

Abstract

In the past, trimethylantimony (TMSb) has been almost exclusively used as the Sb source in organometallic vapor phase epitaxy (OMVPE). However, TMSb decomposes at relatively high temperatures (above 500 °C). For growth at lower temperatures, TMSb is not an optimum choice. In addition, TMSb decomposition produces methyl radicals, a source for carbon contamination. Thus, it is important to investigate alternative Sb precursors. In this letter, we report the use of a newly developed Sb source, triisopropylantimony (TIPSb), for atmospheric pressure OMVPE. It is found that both GaSb and InSb can be grown with good surface morphologies at temperatures between 430 and 600 °C. The high growth efficiencies indicate that there are few parasitic reactions between TIPSb and trimethylgallium (TMGa) or trimethylindium (TMIn). The GaSb layers grown at 500 °C have background hole concentrations of 2×1016 cm−3. Low-temperature photoluminescence (PL) measurements indicate that the acceptor is due to Sb vacancies rather than carbon acceptors. The InSb epilayers have electron concentrations of about 5×1016 cm−3 at 77 K and low-temperature PL shows well-resolved exciton and acceptor-related peaks. These results indicate that TIPSb is a viable source for the OMVPE growth of Sb-containing III-V semiconductors.