Improvement of High-Temperature Stability of Al₂O₃/Pt/ZnO/Al₂O₃ Film Electrode for SAW Devices by Using Al₂O₃ Barrier Layer.

Xingpeng Liu,Bin Peng,Wanli Zhang,Jun Zhu,Xingzhao Liu,Meng Wei

doi:10.3390/ma10121377

Abstract

In order to develop film electrodes for the surface acoustic wave (SAW) devices operating in harsh high-temperature environments, novel Al2O3/Pt/ZnO/Al2O3 multilayered film electrodes were prepared by laser molecular beam epitaxy (LMBE) at 150 °C. The first Al2O3 layer was used as a barrier layer to prevent the diffusion of Ga, La, and Si atoms from the La3Ga5SiO14 (LGS) substrate to the film electrode and thus improved the crystalline quality of ZnO and Pt films. It was found that the resistance of the Al2O3/Pt/ZnO/Al2O3 electrode did not vary up to a temperature of 1150 °C, suggesting a high reliability of electrode under harsh high-temperature environments. The mechanism of the stable resistance of the Al2O3/Pt/ZnO/Al2O3 film electrodes at high temperature was investigated by analyzing its microstructure. The proposed Al2O3/Pt/ZnO/Al2O3 film electrode has great potential for application in high-temperature SAW devices.

Highlights

There has been a long-standing research interest in surface acoustic wave (SAW) sensors for their wide applications in recent years [1,2,3,4]
2O3 electrode was fabricated on LGS to explore its characteristic, from room temperature to 1200 °C
Al2O3 film can be as a suitable layer for by using next. why we focus on the film electrode by using Al2O3 barrier layer

Summary

Introduction

There has been a long-standing research interest in surface acoustic wave (SAW) sensors for their wide applications in recent years [1,2,3,4]. With the progress of science and technology, SAW sensors that operate stably in high temperatures are in high demand [5]. The major challenge in fabricating SAW sensors for operating at high temperatures is to prepare film electrodes which can work stably at high temperatures. The main existing problem is that all the film electrodes undergo rapid agglomeration, recrystallization, and atom diffusion at temperatures higher than 700 ◦ C, resulting in the destruction of film electrodes and the failure of SAW sensors. Great efforts have been made to investigate the working of film electrodes at high temperatures. Rane [9,10] used tungsten film electrodes to prevent the diffusion of Ga and O atoms from the substrate and obtained stable sensors up to 800 ◦ C. Pereira da Cunha [11] investigated a Pt-Ni/Pt-Zr electrode containing an

Methods

Results

Conclusion