CHARACTERISTICS OF ZINC-OXIDE FILMS ON GLASS SUBSTRATES DEPOSITED BY RF-MODE ELECTRON-CYCLOTRON-RESONANCE SPUTTERING SYSTEM

There are two types of electron cyclotron resonance (ECR) sputtering s ystems, DC-mode and RF-mode. In this paper, the properties of zinc oxi de (ZnO) film deposited by an PF-mode ECR sputtering system capable of long-term stable deposition are investigated. It is confirmed for the first time that this system is capable of depositing a ZnO film havin g a sidewall structure without columnar or fibrous grains on an interd igital transducer (IDT)/glass substrate. The ZnO films so deposited we re capable of driving the 1.1 GHz fundamental mode in a Rayleigh surfa ce acoustic wave (SAW) without the large propagation loss at high freq uencies of conventional ZnO films. Furthermore, ZnO films deposited by this system exhibited 1.7 dB lower insertion loss and a closer agreem ent between effective electromechanical coupling factors (k(eff)) and the corresponding values calculated with the finite element method (FE M) in comparison with the films deposited by the DC-mode ECR sputterin g system.