Voltage Linearity and Leakage Currents of Crystalline and Amorphous SrTa2O6 Thin Films Fabricated by Sol-Gel Method

Abstract

Compared crystalline SrTa2O6 (STA), amorphous STA thin film showed a lower dielectric constant (ϵ), but better voltage linearity. Among the amorphous thin films, 700°C annealed thin film showed a high ϵ of about 40, the lowest leakage current of 10−8 A/cm2 and very good voltage linearity with a quadratic voltage capacitance coefficient (α) of 27 ppm/V2. In the crystalline thin film, a negative α with no frequency dependency was observed, suggesting that a dipolar relaxation occurred and caused the larger voltage nonlinearity. The decreasing positive α with increasing frequency property of the amorphous thin films suggested electrode polarization occurred.