The improved Pt/ZnO/Al₂O₃ electrode for high temperature SAW sensors

Abstract

In this study, Pt/ZnO/Al2O3 multilayer film were fabricated on La3Ga5SiO14 substrates as the electrodes of surface acoustic wave (SAW) sensors working at high temperature. The Al2O3 film was employed as the first buffer layer to promote the crystalline qualities of the Pt and ZnO layers. This Pt/ZnO/Al2O3 sample was found to significantly improve the electrode's reliability at high temperature. After high temperature electrical measurement, the varied microstructures of the Pt/ZnO/Al2O3 electrodes were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) to investigate its mechanism for stable resistance. The conductive stability of the Pt/ZnO/Al2O3 film was found to be improved at 800 °C by using Al2O3 buffer layer. This proposed ZnO/Al2O3 double buffer layers have great potential in improving the conductive stability of electrodes for SAW devices at high temperature.