Molecular-beam epitaxial growth of high-quality InSb on InP and GaAs substrates

Abstract

Epitaxial layers of InSb have been grown in InP and GaAs substrates by molecular-beam epitaxy. The dependence of the epilayer quality on flux ratio, JSb4/JIn , was studied. Deviation from an optimum value of JSb4/JIn (∼2) during growth led to deterioration in the surface morphology and the electrical and crystalline qualities of the films. Room-temperature electron mobilities as high as 70 000 and 53 000 cm2/V s were measured in InSb layers grown on InP and GaAs substrates, respectively. Unlike the previous results, the conductivity in these films is n type even at T=13 K, and no degradation of the electron mobility due to the high density of dislocations was observed. The measured electron mobilities (and carrier concentrations) at 77 K in InSb layers grown on InP and GaAs substrates are 110 000 cm2/V s (3×1015 cm−3) and 55 000 cm2/V s (4.95×1015 cm−3), respectively, suggesting their application to electronic devices at cryogenic temperatures.