In response to the rapid development of wireless communication, enhancement of temperature stability and power durability for surface acoustic wave (SAW) devices is both scientifically and technologically important in the 5G era. This paper discusses the utilization of 5-layer electrode Ti/Cu/Ti/Cu/Ti to the development of high power and low loss temperature-compensated surface acoustic wave (TC-SAW) filters. By modulating the microstructure of 5-layer electrode, the power durability can be increased to 1.7 times that of the conventional 3-layer electrode, while the life time to failure can be enhanced by 10 ⁴ times. Through the cross section analysis of devices before and after power test, it is found that the deformation mainly concentrates on the bottom edge of electrode, whose result matches well with finite element method (FEM) simulation. The enhancement of power durability can be attributed to high resistance to cyclic stress in the bottom fine grain area. Furthermore, substrate failure areas due to Ti diffusion were also observed, which may be caused by the high temperature due to the current concentration around the electrode deformation. Our results show that the 5-layer electrode configuration is a promising solution for high power TC-SAW filter without deterioration of radio frequency performance and temperature coefficient of frequency.

中文翻译：

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Ti/Cu/Ti/Cu/Ti电极TC-SAW滤波器的功率耐久性增强及失效分析

为应对无线通信的快速发展，提高声表面波（SAW）器件的温度稳定性和功率耐久性在 5G 时代具有重要的科学和技术意义。本文讨论了利用 5 层电极 Ti/Cu/Ti/Cu/Ti 开发高功率低损耗温度补偿表面声波 (TC-SAW) 滤波器。通过调整5层电极的微观结构，功率耐久性可以提高到传统3层电极的1.7倍，而失效寿命可以提高10 ⁴次。通过对功率测试前后器件的截面分析，发现变形主要集中在电极的底部边缘，其结果与有限元法（FEM）模拟吻合较好。功率耐久性的增强可归因于底部细晶粒区域对循环应力的高抵抗力。此外，还观察到由于 Ti 扩散导致的基板失效区域，这可能是由于电极变形周围的电流集中导致的高温引起的。我们的结果表明，5 层电极配置是高功率 TC-SAW 滤波器的有前途的解决方案，而不会降低射频性能和频率温度系数。