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

摘要

Electronic conduction in sputtered Ta{sub}2O{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}2O{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, Le. 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.