The use of triisopropylantimony for the growth of InSb and GaSb

Abstract

A newly developed Sb source, triisopropylantimony (TIPSb), has been successfully used to grow InSb and GaSb epilayers by atmospheric pressure organometallic vapor phase epitaxy (OMVPE). Both GaSb and InSb have been grown with excellent morphologies. Growth efficiencies indicate that there are no parasitic reactions between TIPSb and trimethylgallium (TMGa) or trimethylindium. For GaSb growth, the temperatures have been varied between 500 and 600 °C. V/III ratios close to unity are necessary to obtain the best morphologies at 600 °C. As the growth temperature is decreased, lower V/III ratios are required. This is because TMGa decomposition is incomplete and TIPSb decomposes completely at these temperatures. 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. A major advantage of TIPSb is that it decomposes at temperatures much lower than that for trimethylantimony (TMSb). InSb with good morphologies can be grown using V/III ratios close to unity at temperatures as low as 430 °C. On the other hand, growth temperatures higher than 500 °C are necessary for the growth of InSb using TMSb with V/III ratios of close to 1. For temperatures lower than 430 °C, InSb can be grown using TIPSb, but higher V/III ratios are required due to incomplete TIPSb pyrolysis. 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.