TERTIARYBUTYLDIMETHYLANTIMONY FOR INSB GROWTH

Trimethylantimony (TMSb) is the standard Sb source for OMVPE growth of Sb-containing materials. However, TMSb pyrolyzes slowly for temperatures below 500-degrees-C, limiting its usefulness for low temperature growth. Recently, triisopropylantimony (TIPSb) has successfully been used to grow InSb. This allows the growth of high quality layers at V/III ratios near unity for temperatures as low as 430-degrees-C. For lower temperatures, higher V/III ratios are required due to incomplete TIPSb pyrolysis. This causes problems for the small bandgap materials which require growth temperatures lower than 400-degrees-C. In this work, tertiarybutyidimethylantimony (TBDMSb) is used, together with trimethylindium (TMIn), for the growth of InSb. The optimum V/III ratio is near unity for growth temperatures from 375 to 450-degrees-C. Good surface morphology InSb layers can also be obtained at temperatures as low as 350 and 325-degrees-C at moderate V/III ratios of 10 and 17, respectively. Using this new Sb source, the growth temperature can be reduced by more than 100-degrees-C as compared to TMSb, and about 50-degrees-C as compared to TIPSb. Another advantage of using TBDMSb is that the surface morphology for InSb grown using TBDMSb does not depend on V/III ratio as critically as for InSb grown using TIPSb. Moreover, the growth efficiency is high, on the order of 1 x 10(4) mum/mol, for temperatures higher than 400-degrees-C. This indicates that there are minimal parasitic reactions between TMIn and TBDMSb. The electron concentration is near 10(16) cm-3 for growth temperatures of between 450 and 375-degrees-C. It increases slightly to approximately 10(17) cm-3 for T(g) = 350 and 325-degrees-C. The 10 K photoluminescence spectra show well-resolved peaks due to exciton and impurity recombination. Samples grown at temperatures higher than 400-degrees-C exhibit higher photoluminescence intensities than those grown at lower temperatures. The results indicate that TBDMSb is an excellent replacement for TMSb and TIPSb for the growth of InSb.