TRISDIMETHYLAMINOANTIMONY - A NEW SB SOURCE FOR LOW-TEMPERATURE EPITAXIAL-GROWTH OF INSB

Many new Sb sources for organometallic vapor phase epitaxial (OMVPE) g rowth of low energy band gap III/V antimonides have been developed and tested. However, most of the precursors including trimethylantimony ( TMSb), triisopropylantimony (TIPSb), diisopropylantimonyhydride (DIPSb H), and tertiarybutyldimethylantimony (TBDMSb) have significant drawba cks such as inefficient pyrolysis at low temperatures or high levels o f carbon contamination in the materials produced. In this work, a new Sb source, trisdimethylaminoantimony (TDMASb) [Sb(N(CH3)(2))(3)], has been used with trimethylindium (TMIn) for the growth of InSb epitaxial layers by atmospheric pressure OMVPE. This precursor is found to be p articularly effective at low growth temperatures. V/III ratios for gro wth of good morphology layers were less than 3 for growth temperatures of 300 to 425 degrees C. A V/III ratio of less than 1 was optimum at 275 degrees C since the TDMASb pyrolyzes more efficiently than TMIn at this temperature. Higher growth efficiencies (growth rate/group III m olar flow rate) were observed than for other Sb precursors for growth temperatures below 400 degrees C. From the photoluminescence (PL) spec tra and X-ray diffraction data, it was confirmed that good InSb crysta llographic quality was obtained for growth temperatures from 425 to as low as 275 degrees C. For the first time, PL at 10 K has been observe d from InSb epitaxial layers grown at 300 degrees C. The free electron concentrations of the InSb epitaxial layers were measured to be betwe en 2.7 X 10(16) and 5 x 10(17) cm(-3) over the entire range of growth temperature. Thus, the very high levels of carbon incorporation measur ed for low-temperature growth using several other Sb precursors was av oided using TDMASb. These results indicate that the new Sb precursor, TDMASb, is excellent for OMVPE growth of InSb and appears to be the be st source to date for low temperature growth.