摘要:
薄膜体声波谐振器(FBAR)的谐振频率会受到外界环境温度的影响而产生漂移,对于FBAR滤波器而言,这种温度-频率漂移特性会导致其中心频率、插入损耗、带内纹波等性能发生变化,降低其在电学应用中的可靠性。应用ANSYS有限元分析软件,对一个典型Mo-AlN-Mo三层结构的FBAR进行了温度-频率漂移特性的仿真,得到其在［－50 ℃, 150 ℃］温度范围内的频率温度系数(TCF)约为－3510－6/℃。在FBAR叠层薄膜结构中添加了一层具有正温度系数的二氧化硅温度补偿层,分析了该补偿层厚度对FBAR的温度-频率漂移特性、谐振频率和机电耦合特性的影响。设计了具有一层二氧化硅温度补偿层的FBAR叠层,由Mo/AlN/SiO2/Mo多层薄膜构成,仿真得到其频率温度系数为0.87210－6/℃；与没有温度补偿层的FBAR相比,温度稳定性得以显著改善。关键词: Abstract: Key words:
Abstract:
The property of temperature-frequency drift has an effect on the passband ripples, center frequency and insertion loss of film bulk acoustic resonator (FBAR) filters, reducing the reliability of its electrical application. A temperature-frequency drift simulation of a typical Mo/AlN/Mo 3-layered FBAR is achieved using finite element analysis software ANSYS, and the simulated temperature coefficient of frequency is about －3510－6/℃ within the temperature range ［－50 ℃, 150 ℃］. By adding a SiO2 temperature compensated layer with positive temperature coefficient in the FBAR stacked films structure, the effects of the compensated layer thickness on temperature-frequency drift, resonant frequency and electromechanical coupling are analyzed. The simulated temperature-frequency coefficient of the FBAR stack with a SiO2 temperature compensated layer, which is composed of Mo/AlN/SiO2/Mo multi-layer films, is about 0.87210－6/℃, which shows significantly improved temperature stability compared to that without the temperature compensated layer.
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