Piezoelectric and optical properties of ZnO films deposited by an electron-cyclotron-resonance sputtering system

摘要

An electron-cyclotron-resonance (ECR) sputtering system enables the production of highly ionized plasma under low gas pressure, and it is considered that a ZnO film deposited by the ECR sputtering system is of higher quality than the one deposited by a conventional sputtering system. The ZnO films deposited on glass or sapphire substrates by ECR sputtering exhibited a high electrical resistivity (ρ>10~10 Ωcm), excellent piezoelectric properties (generating strongly higher-frequency surface acoustic waves and having a larger electromechanical coupling factor), and good optical properties (showing free excitons on R-sapphire at 2 K and on c-sapphire at room temperature).