Interface and dielectric properties of the n-indium-phosphide–silicon-oxide system

The small signal conductance and capacitance of metal/silicon oxide/n‐indium‐phosphide structures have been measured as a function of bias voltage at various frequencies from 1 to 100 kHz. The conductance method has been used to determine the surface state density, which rises as the conduction band is approached, passing through 3×1012 cm−2 eV−1 at an energy 30 meV below the conduction band edge. The data display a strong frequency and temperature dependence as the semiconductor approaches accumulation. The dispersion in this region fits a Maxwell–Wagner model suggesting that such effects are caused by the inhomogeneous nature of the dielectric in our samples.