Precise electrical evaluation of active oxides thickness and comparison with TEM measurements

In this paper we propose a new model to describe the quantum effects at the SiO2/Si interface of metal-oxide–semiconductor (MOS) devices. Using this model we developed a method to extract the thickness of thin oxides (in the range of 3–20 nm) from capacitance (C) as a function of voltage (V) measurements, C(V). The results of our extraction are in good agreement with transmission electron microscopy (TEM) measurements, within the accuracy of both techniques, while classical electrical methods are inadequate for a precise evaluation of the oxide thickness. Moreover this new method is suitable for in-line monitoring of oxide thickness in advanced MOS processes.