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

Low growth temperatures are necessary for the organometallic vapor pha se epitaxial growth of many III/V semiconductors, particularly the low energy band gap antimonides. This has caused difficulties with conven tional, established precursors because of low pyrolysis efficiencies a t low temperatures and large amounts of carbon contamination in the so lid. This paper gives the first results of the use of a new precursor, diisopropylantimonyhydride (DIPSbH), (C3H7)2SbH. It has been used wit h trimethylindium (TMIn) to produce InSb epitaxial layers at temperatu res as low as 275-degrees-C with values of V/III ratio of approximatel y 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. P hotoluminescence spectra could be measured for layers grown at 325-deg rees-C and above. The spectra are similar to those from commercial InS b substrates. Van der Pauw measurements indicate that the free electro n concentration of the InSb increases dramatically as the growth tempe rature is lowered. Layers grown at 300-degrees-C have donor densities in excess of 10(19) cm-3. The donor concentrations are much higher tha n for InSb grown using tertiarybutyldimethylantimony, another low-temp erature Sb precursor. SIMS measurements indicate that the donor is car bon.