Some Properties of RF Sputtered Al2 O 3 ‐ Ta2 O 5 Composite Thin Films

Abstract

composite dielectric thin films were prepared by RF plasma sputtering under various preparation conditions. Secondary ion mass spectroscopy and x‐ray photoelectron spectroscopy were used to investigate the impurities and the oxygen vacancies in the films. The main impurity of the film was Na, but the sodium can be reduced by the use of high purity (5N) Al‐Ta metal target. Oxygen vacancies were mainly related to Ta atoms and were dependent on the deposition rate of the films. Films sputtered at around 50 Å/min were found to be relatively good for thin film devices, i.e., they have a high dielectric constant , a low leakage current (∼30 mA/F, at 10 V), and fewer oxygen vacancies. The preparation, details of the structure, and some electrical properties of the composite dielectric thin films are described.