OMVPE growth of InAsSb using novel precursors

Abstract

InAs, InSb, InAsSb and the related bismuth containing alloys are useful materials for infrared applications. A significant effort has been expended to develop new group III and group V precursors for organometallic vapor phase epitaxial (OMVPE) growth of these materials at low temperatures. We report the first use of a rarely studied group III source, triisopropylindium (TIPIn), together with the novel As and Sb precursors tertiarybutylarsine (TBAs) and tertiarybutyldimethylantimony (TBDMSb) for the growth of InAs and InAsSb epitaxial layers by atmospheric pressure OMVPE. InAs layers with good surface morphologies were obtained for growth temperatures as low as 300°C and low values of frsol|V/III ratio. Use of a high total flow rate and a reactor having a small volume upstream of the substrate alleviates the parasitic reaction problems reported earlier. This results in 3–5 × increase in the growth efficiency. Values of room temperature electron concentration, n, for InAs samples were found to range between 3 × 10 18 cm −3 for layers grown at 300°C to 9 × 10 16 cm −3 for layers grown at 400°C. These values of n are about an order of magnitude less than previously reported for InAs grown at the same temperature using either TMIn or EDMIn with AsH 3 or TBAs. InAs 1− x Sb x (0 < x < 0.7) layers were grown at 350°C with excellent surface morphologies for low frsol|V/III ratios. The layers have free electron concentrations ranging from 9 × 10 16 to 4 × 10 17 cm −3. X-ray diffraction data and 10 K photoluminescence spectra indicate that both the InAs and InAsSb layers grown at low temperatures using the new precursor combination are far superior to layers grown using other precursors.