Physical modeling of electrical and dielectric properties of high-k ta2o5 based MOS capacitors on silicon

Abstract

In this paper we present an integral physical model for describing electrical and dielectric properties of MOS structures containing dielectric stack composed of a high-k dielectric (with emphasize on pure and doped Ta2O5) and an interfacial silicon dioxide or silicon oxynitride layer. Based on the model, an equivalent circuit of the structure is proposed. Validity of the model was demonstrated for structures containing different metal gates (Al, Au, Pt, W, TiN, Mo) and different Ta2O5 based high-k dielectrics, grown of bare or nitrided silicon substrates. The model describes very well the I-V characteristics of the considered structures, as well as frequency dependence of the capacitance in accumulation. Stress-induced leakage currents are also effectively analyzed by the use of the model.