Nonlinear capacitance variations in amorphous oxide metal-insulator-metal structures

An analytical model for the electric field and temperature dependence of the nonlinear dielectric susceptibility of amorphous oxides is developed and compared with experimental measurements on metal-insulator-metal capacitors. Using the model, experimental capacitance variations with applied field, as well as temperature, are tied to an increase in system entropy due to thermal expansion of the lattice. In addition, our model explains the CV-curve sign reversal (slope of the capacitance versus voltage curve) that is frequently seen for metal oxide versus SiO2 capacitors. (C) 2007 American Institute of Physics.