Quantum effects on the extraction of MOS oxide traps by 1/f noise measurements

Abstract

1/f noise measurements can be a viable method for the characterization of the oxide state density in MOSFETs, being directly applicable to submicron-scale devices. In this work we address the impact of electron quantization and mobility fluctuations on the analysis of the 1/f noise results, assessing the precision of the approximations usually introduced in the extraction procedure. Numerical models are employed to account for quantization effects, both in the normal and the lateral directions with respect to the Si-SiO/sub 2/ interface. Mobility fluctuations are analyzed by means of a state-of-the-art model for Coulomb-limited mobility. Results are reported for n-MOSFETs with a heavy channel doping. It is found that incomplete knowledge of the spatial location and nature (acceptor- or donor-like) of traps causes a substantial uncertainty in the extracted value of the absolute trap density.