Dielectric study of thin films of Ta/sub 2/O/sub 5/ and ZrO/sub 2/

Electronic conduction in sputtered Ta/sub 2/O/sub 5/ and ZrO/sub 2/ thin films have been studied using impedance spectroscopy, isothermal transient ionic current, and current-voltage measurements. The dielectric properties of Ta/sub 2/O/sub 5/ were shown to be sensitively dependent on deposition parameters with two different frequency responses: a flat loss behavior with very low DC conductivity, or a relaxation peak together with a somewhat higher DC conductivity. ZrO/sub 2/ has different dielectric properties when fresh, i.e. newly deposited, or aged. A fresh sample arbitrarily can show two different behaviors, consisting of a DC conductivity with a relaxation peak superimposed on it. The DC conductivity shows either of two different values. The aged sample has a lower permittivity and DC conductivity, and the relaxation peak is found at much lower frequencies. Fresh samples of ZrO/sub 2/ also show switching behavior.