Extraction of the oxide thickness using a MOS structure quantum model for SiO2 oxide <5 nm thick films

In this paper, we present a full quantum model of metal oxide semiconductor capacitance based on a self-consistent resolution of Schrodinger and Poisson equations. The model is used in accumulation to extract the oxide thickness of N+ polycrystalline silicon-SiO2-P silicon capacitors in the range 2-5 nm. The extraction results are in agreement with reference ellipsometric measurements to < +/- 14%. We also show the necessity of a quantum computation of the gate capacitance for high substrate doping and low oxide thickness. The influence of the tunneling current is also discussed. (C) 2001 Elsevier Science B.V. All rights reserved.