Dielectric and mechanical properties of anodic films in the Ta–Ti system

Abstract

AbstractAnodic oxidation at high efficiency of sputtering‐deposited Ta–Ti alloys containing 0.6–40 at.% Ti is shown to result in amorphous films comprising a relatively thin outer layer of TiO2‐based material and an inner layer consisting of units of TiO2 and Ta2O5. The two layers develop due to the faster migration of Ti4+ ions in the inner layer relative to that of Ta5+ ions. The formation ratios for the various films are in the approximate range 1.6–1.9 nm V−1. The dielectric constants of the films are ∼28, which is a similar value to that of anodic tantala. Nanoindentation revealed that the elastic modulus and hardness of the films are essentially independent of film composition, with average values of 134 and 5.3 GPa, respectively. Copyright © 2003 John Wiley & Sons, Ltd.