Transport measurements on InP inversion metal-oxide semiconductor transistors

Abstract

Using recently developed InP metal-oxide-semiconductor field-effect transistors with SiO2 gate insulation, the transport properties of electrons in (100) inversion layers are investigated for surface carrier densities up to 7×1012 cm−2. Conductivity and magnetoconductivity measurements are analyzed in magnetic fields up to 19.7 T at 4.2 K. The depletion charge is varied in the range 0.56–1.66×1012 cm−2. The carriers in the surface channel behave like a quasi two-dimensional electron gas. From the surface quantum oscillations, it is possible to determine the density of free carriers in the surface layer and the threshold voltage. A second electric subband is occupied at surface carrier concentrations above Ninv =4.5×1012 cm−2. The effective mobility is dominated by Coulomb and surface roughness scattering. The characteristic parameters for the two scattering mechanisms are evaluated.