OMVPE GROWTH OF INASSB USING NOVEL PRECURSORS

InAs, InSb, InAsSb and the related bismuth containing alloys are usefu l materials for infrared applications. A significant effort has been e xpended to develop new group III and group V precursors for organometa llic vapor phase epitaxial (OMVPE) growth of these materials at low te mperatures. We report the first use of a rarely studied group III sour ce, triisopropylindium (TIPIn), together with the novel As and Sb prec ursors tertiarybutylarsine (TBAs) and tertiarybutyldimethylantimony (T BDMSb) for the growth of InAs and InAsSb epitaxial layers by atmospher ic pressure OMVPE. InAs layers with good surface morphologies were obt ained for growth temperatures as low as 300 degrees C and low values o f V/III ratio. Use of a high total flow rate and a reactor having a sm all volume upstream of the substrate alleviates the parasitic reaction problems reported earlier. This results in 3-5 X increase in the grow th efficiency. Values of room temperature electron concentration, n, f or InAs samples were found to range between 3 X 10(18) cm(-3) for laye rs grown at 300 degrees C to 9 X 10(16) cm(-3) for layers grown at 400 degrees C. These values of n are about an order of magnitude less tha n previously reported for InAs grown at the same temperature using eit her TMIn or EDMIn with AsH3 or TBAs. InAs1-xSbx (0 <x <0.7) layers wer e grown at 350 degrees C with excellent surface morphologies for low V /III ratios. The layers have free electron concentrations ranging from 9 x 10(16) to 4 x 10(17) cm(-3). X-ray diffraction data and 10 K phot oluminescence spectra indicate that both the InAs and InAsSb layers gr own at low temperatures using the new precursor combination are far su perior to layers grown using other precursors.