Determination of deep ultrathin equivalent oxide thickness (EOT) from measuring flat-band C-V curve

In this letter, a novel and simple method to determine deep ultrathin oxide thickness by measuring the MOS capacitance under the flat-band condition is reported. The mechanism of this method has been profoundly studied. The results determined by this method show good agreement with those using capacitance-voltage (C-V) simulation, ellipsometer, and high-resolution transmission electromicroscopy (HRTM) analysis for thin oxides (2/spl sim/3 nm). The thickness of pure oxide extracted by this method in this experiment can be down to 1.4 nm despite the obvious C-V distortion.