Effect of Ta2O5 Doping on Electrical Characteristics of SrTiO3 Metal-Insulator-Metal Capacitors

Abstract

The effect of Ta2O5 doping on electrical characteristics of SrTiO3 (STO) metal-insulator-metal (MIM) capacitors was studied for the first time. Using Ta2O5-doped STO dielectrics, an absolute quadratic voltage coefficient of capacitance (VCC-alpha) of 510 ppm/V-2 and a high capacitance density of similar to 20 fF/mu m(2) are achieved. These are approximately one order of magnitude lower than those of the MIM capacitor fabricated using a pure STO. In addition, the degradation of electrical properties (capacitance variation versus voltage, VCC-alpha, and long-term reliability) after electrical stressing is reduced, compared with that of an MIM capacitor fabricated using a pure STO. (C) 2009 The Japan Society of Applied Physics