Molecular-beam epitaxial growth of InSb on GaAs and Si for infrared detector applications

Abstract

InSb epitaxial films were grown on GaAs and Si substrates by molecular-beam epitaxy using an intermediate AlSb buffer layer. The use of an AlSb intermediate buffer layer greatly facilitates the overgrowth of InSb on significantly lattice-mismatched foreign substrates, such as GaAs and Si. Hall mobility, x-ray rocking curve, and infrared absorption measurements were performed to characterize the samples. Using a 300 nm AlSb buffer layer, 3 μm thick InSb films on GaAs and Si substrates with room-temperature electron mobilities as high as 55 000 cm2 V−1 s−1 were routinely achieved. X-ray rocking curve linewidths of 199 arcsec for InSb on GaAs and 230 arcsec for InSb on Si have been achieved, which represent the best results to date. Our results indicate that AlSb is a very effective buffer layer for InSb devices grown on GaAs and Si substrates.