The characterization of p-type InAs for superconductor/semiconductor devices

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Abstract
Metal-oxide-semiconductor (MOS) structures on (100)-orientated p-type InAs are fabricated to study the influence of different patterning processes like anodization and etching on the electronic properties of the native inversion layer which forms a quasi two-dimensional electron gas (2DEG). We have optimized the preparation process for MOS structures with combined Nb2O5/SiO2 gate oxides made by the selective niobium anodization process (SNAP) and plasma-enhanced chemical vapour deposition (PECVD) as well as for MOS structures with chemically etched surfaces. The surface carrier density, the electron mobility and the effective subband masses determined from magnetotransport measurements are compared with the ones of MOS samples with SiO2 gate oxides on surfaces that have been chemically polished with a bromine-in-methanol solution. Our main result is that surface roughness scattering is the dominant mechanism influencing the electron mobility. The investigations of the native inversion layer on p-type InAs are important for the development of superconductor/semiconductor/superconductor (S/Sm/S) devices because their superconducting features strongly depend on the normal conducting transport properties.