Here, deposition of SiO₂ film by RF-sputtering onto the anodic Ta₂O₅ film for fabrication of an SiO₂-Ta₂O₅ thin film capacitor is reported. Reproducible film deposition rate is achieved within the accuracy of 3% by decreasing the influence of adsorbed gases in the vacuum chamber. Argon pressure is adjusted in order to obtain the uniform deposition of the SiO₂ film. The thickness distribution is less than 3% within the area covered by 70% of target radius. The standard deviation of capacitance due to the distribution of SiO₂ films is about 2.5% of the average capacitance.
The substate temperature should be precisely controlled during RF-sputtering for the realization of the capacitor with excellent electrical characteristics. The high substrate temperature causes deterioration of Ta₂O₅, but the SiO₂ film deposited at low temperature has poor life stability and large capacitance change in moisture. The optimum substrate temperature is about 150 °C for the SiO₂ film deposition onto the anodic Ta₂O₅ film.