A model for capacitance reconstruction from measured lossy MOS capacitance-voltage characteristics

Abstract

A capacitance model is developed and a correction formula is derived to reconstruct the intrinsic oxide capacitance value from measured capacitance and conductance of lossy MOS devices. Due to discrepancies during processing, such as cleaning, an unwanted lossy dielectric layer is present in the oxide/semiconductor interface causing the measured capacitance in strong accumulation to be frequency dependent. The capacitance-voltage characteristics after correction are free from any frequency dispersion effect and give the actual oxide thickness in accumulation at all frequencies. Simulation of the measured capacitance-frequency curve was carried out using the model. The model was applied to SiO2/Si, SiO2/strained Si and GaO2/GaAs MOS capacitors.