Deposition and piezoelectric characteristics of ZnO films by using an ECR sputtering system

Piezoelectric properties of ZnO films, were investigated by using an Electron Cyclotron Resonance (ECR) sputtering system. It was confirmed that this system was capable of depositing a ZnO film with a large specific resistance, and good c-axis orientation on an interdigital transducer (IDT)/glass substrate at a low temperature (less than 200/spl deg/C) and in a low gas pressure (/spl sim/10/sup -4/ torr). Furthermore, these ZnO films exhibited excellent SAW characteristics (insertion losses) and effective electromechanical coupling factors (k/sub eff/) compared with ZnO films deposited by a conventional RF magnetron sputtering system. Further, this ECR sputtering system was capable of depositing a ZnO film, without heating the substrate, that was capable of propagating a Rayleigh SAW at 700 MHz for the first time. >