Energy and electric field dependence of Si-SiO2 interface state parameters by optically activated admittance experiments

Abstract

By means of a recently developed experimental technique, the dependence on the energy and electric field of Si-SiO2 interface state capture cross sections has been measured for Al-SiO2-nSi structures with an oxide thickness ?800 Å. The capture cross section for holes,σp, has been observed to be several orders of magnitude larger than that for electron, σn, and further it has been observed to show a strong dependence on energy in the upper half of the silicon energy gap. This apparent dependence of σp on energy has been shown to arise primarily from a dependence on the electric field at the semiconductor surface. For the same electric field, interface states at different energies in the gap are observed to have very nearly the same magnitude of capture cross section.