DETERMINATION OF THE INTERFACE-TRAP DENSITY IN METAL-OXIDE-SEMICONDUCTOR FIELD-EFFECT TRANSISTOR THROUGH SUBTHRESHOLD SLOPE MEASUREMENT

Interface trap densities at gate oxide/silicon substrate (SiO2/Si) interfaces of metal oxide semiconductor field-effect transistors (MOSFETs) were determined measuring the substrate bias dependence of the subthreshold slope. This method enables the characterization of interface traps residing between the midgap and strong inversion (2 times the Fermi potential) of small MOSFETs. In consequence of the high accuracy of this method, the energy dependence of the interface trap density is more reliable. 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, substrate dopant concentration obtained as a by-product through this technique also showed good agreement with the result obtained through the body effect measurement.