Surface potential determination in irradiated MOS transistors combining current-voltage and charge pumping measurements

A method combining charge pumping and current-voltage measurements is presented for determining the surface potential versus gate voltage relationship in irradiated MOS transistors. This technique uses parameter optimization and simple numerical equations. It can be applied even for a high interface state density and for a non-uniform distribution in the silicon bandgap. This makes the method attractive for all studies concerning interface trap characterization or accurate modeling of MOS transistors in subthreshold regime. In this study, this new approach is applied to n-channel transistors irradiated up to 10 Mrad (SiO₂)