DIISOPROPYLANTIMONYHYDRIDE (DIPSBH) FOR LOW-TEMPERATURE EPITAXIAL-GROWTH OF INSB

Low growth temperatures are necessary for the organometallic vapor phase epitaxial growth of many III/V semiconductors, particularly the low energy band gap antimonides. This has caused difficulties with conventional, established precursors because of low pyrolysis efficiencies at low temperatures and large amounts of carbon contamination in the solid. This paper gives the first results of the use of a new precursor, diisopropylantimonyhydride (DIPSbH), (C3H7)2SbH. It has been used with trimethylindium (TMIn) to produce InSb epitaxial layers at temperatures as low as 275-degrees-C with values of V/III ratio of approximately 2.5. In this regard, it is the best Sb precursor tested to date for low temperature growth. The morphology and crystallographic quality of the epitaxial layers are acceptable for semiconductor applications. Photoluminescence spectra could be measured for layers grown at 325-degrees-C and above. The spectra are similar to those from commercial InSb substrates. Van der Pauw measurements indicate that the free electron concentration of the InSb increases dramatically as the growth temperature is lowered. Layers grown at 300-degrees-C have donor densities in excess of 10(19) cm-3. The donor concentrations are much higher than for InSb grown using tertiarybutyldimethylantimony, another low-temperature Sb precursor. SIMS measurements indicate that the donor is carbon.