Characterization of carbon-doped InSb diode grown by molecular beam epitaxy

Abstract

Carbon-doped p-type InSb layers grown by solid source molecular beam epitaxy are characterized using a p+–n diode structure. Based on the combination of current–voltage, secondary ion mass spectroscopy and x-ray diffraction measurements, carbon is proven to be an effective p-type dopant for InSb with hole concentration reaching the range of 1019 cm−3. It is also proven that the use of the Hall effect to determine the hole concentration in the p-type InSb layer may be unreliable in cases where the leakage current in the p+–n junction is high. A thermal trap-assisted tunnelling model with two trap levels successfully explains the origin of leakage current mechanisms in the carbon-doped InSb samples. Good agreement between measured and calculated dc characteristics of the diodes at reverse bias up to −3 V from 30 to 120 K supports the validity of the current transport model.