Dielectric properties of films prepared by the reactive sputtering of Ta In [formula omitted] mixtures

Abstract

The dielectric properties of amorphous films prepared by reactively sputtering tantalum in oxygen-nitrogen mixtures have been measured. As the nitrogen content in the sputtering discharge was increased, the dielectric constant decreased from 26 to 16 and the films became more suitable for capacitor fabrication ( i.e. had lower leakage currents and higher breakdown voltages). Comparison with reported results for anodic films indicates that the nitrogen concentration in the films reached approximately 7 at.% at the lowest dielectric constant. Sputtered tantalum films were found to be suitable for base electrodes, whereas aluminum electrodes significantly increased the capacitor leakage currents.