In this article, we investigate the frequency-dependent voltage nonlinearity effect of high-kappa Ni/SrTiO3/TaN and TaN/SrTiO3/TaN radio-frequency (rf) metal-insulator-metal (MIM) capacitors by electrical and thermal stresses. The experimental results demonstrated that the MIM-related capacitance properties, dependence of voltage and frequency, are not only affected by intrinsic dielectric properties but also shared by extrinsic effect, which possibly originated from the oxygen vacancies or electrode polarization. The high work-function Ni electrode can prevent the frequency-dependent voltage coefficient of capacitance characteristics from deterioration under the high temperature or continued voltage-stressing environments. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3491490] All rights reserved.