纳米多层电极增强声表面波滤波器功率耐受性的研究

Power Durability Enhancement of Surface Acoustic Wave Filter with Multilayer Electrodes

移动通信技术的快速发展对声表面波滤波器性能提出了更高的要求,输入功率的提升和尺寸的减小使得器件上的功率密度急剧上升,亚微米级别的铝叉指电极在高功率下会发生声迁移从而导致器件失效,因此如何使器件在高功率下稳定地工作已经成为声表面波领域亟待解决的关键科学问题。针对铝电极抗声迁移能力差的难点,本文采用有限元方法计算了叉指应力分布并阐明了其工作中最薄弱的部位,基于此针对性地设计并制备了Al-0.9 wt.%Cu(Al-Cu)/Ti/Cu/Ti纳米多层复合电极,以期提升器件的功率耐受性。通过X射线衍射、原子力显微镜、透射电镜等手段表征薄膜织构和微观结构,揭示电极微结构状态对器件功率耐受性的影响。功率测试结果表明,基于Al-Cu/Ti/Cu/Ti多层复合电极的声表面波滤波器最大承受功率达到34.5 dBm(2.81 W),是Al-Cu/Ti电极滤波器的1.78倍。本文为5G时代高功率声表面波器件提供了一种成本低廉、制备简单的电极材料方案。

The rapid development of mobile communication puts higher requirements on performance of surface acoustic wave(SAW)filters.With the enhancement of input power and scale miniaturization,the power density of SAW device increases sharply.Acoustomigration of Al interdigital transducers(IDT)electrodes occurs at high power density results in device failure,and thus how to make the device work stably at high power has become a key scientific issue in SAW industry.Aiming at the difficulty of poor anti-acoustomigration ability of Al electrode,the finite element method was used to calculate the stress distribution and reveal the weakest part.According to the stress distribution,multilayer electrode Al-0.9 wt.%Cu(Al-Cu)/Ti/Cu/Ti was designed and prepared,which is desirable to improve the power durability of the device.X-ray diffraction,atomic force microscopy,transmission electron microscopy were used to characterize the texture and microstructure of the IDT electrodes,and revealed the influence of the electrode microstructure state on the power durability of the SAW filter.The power test demonstrated that the power durability of SAW filter with multilayer electrode reaches 34.5 dBm(2.81 W),which is 1.78 times that of the Al-Cu/Ti electrode.This work provides a low cost and easy preparation electrode solution for high power durable SAW devices in the 5G era.