Piezoelectric properties of zinc oxide films on glass substratesdeposited by RF-magnetron-mode electron cyclotron resonance sputteringsystem

摘要

There are various types of electron cyclotron resonance (ECR)nsputtering systems, DC-mode, RF-mode, etc. We reported that zinc oxiden(ZnO) films on glass substrates deposited by DC-mode ECR and RF-mode ECRnsputtering systems had shown excellent piezoelectric properties andnc-axis orientations. The RF-mode ECR sputtering system was capable ofndepositing ZnO films on glass substrates without evidence of column andnfiber grains in cross section and driving a 1.1 GHz fundamental Rayleighnsurface acoustic wave (SAW). In this paper, the properties of ZnO filmndeposited by an RF-magnetron-mode ECR sputtering system, which has addednmagnets to the outside of a cylindrical zinc metal (Zn) target of thenRF-mode ECR sputtering system, are investigated. It is confirmed thatnthe SAW filters using ZnO films on an interdigital transducern(IDT)/glass substrate deposited by the RF-magnetron-mode ECR sputteringnexhibit almost the same effective electromechanical coupling factorsn(keff) as the theoretical keff values calculated by finite elementnmethod (FEM) using the constants of ZnO single crystal (measured keffnvalues are 97% of the theoretical values) and 0.6~3.7 dB lower insertionnloss in comparison with the films deposited by the DC-mode ECR and thenRF-mode ECR sputtering system