IONIC-CONDUCTIVITY OF TANTALUM OXIDE BY RF-SPUTTERING

Tantalum oxide thin films were prepared by rf sputtering. The dependence of deposition conditions (i.e. sputtering power, total sputtering pressure, and oxygen partial pressure) on ionic resistivities for tantalum oxide films were evaluated. The proton conductivities varied from 3.3 x 10(-6) S/cm to < 10(-10) S/cm. The activation energy for ion motion varied from 0.25 to 0.4 eV; increasing exponentially with the optical absorption coefficient of the films. Variation in the ionic conductivities could be attributed to changes in the carrier concentrations and mobilities; although, a quantitative assessment was not made.