A New Method for Extracting Interface Trap Density in Short-Channel MOSFETs from Substrate-Bias-Dependent Subthreshold Slopes

Abstract

Interface trap densities at gate oxide/silicon substrate (SiO2/Si) interfaces of metal oxide semiconductor field-effect transistors (MOSFETs) were determined from the substrate bias dependence of the subthreshold slope measurement. This method enables the characterization of interface traps residing in the energy level between the midgap and that corresponding to the strong inversion of small size MOSFET. In consequence of the high accuracy of this method, the energy dependence of the interface trap density can be accurately determined. The application of this technique to a MOSFET showed good agreement with the result obtained through the high-frequency/quasi-static capacitance-voltage (C-V) technique for a MOS capacitor. Furthermore, the effective substrate dopant concentration obtained through this technique also showed good agreement with the result obtained through the body effect measurement.