乐甫波器件温度特性实验研究

An Experimental Study on the Temperature Characteristics of Love Wave Devices

研究了基于ST-90°X石英基片和SU-8波导层的乐甫波器件的温度特性。采用电极宽度控制单向单相（EWC/SPUDT）结构和铝电极,设计制作了具有单一模式控制功能和低插入损耗的150 MHz剪切型声表面波（SH-SAW）延迟线器件,并在其表面涂覆不同膜厚的SU-8声波导层构成系列乐甫波器件。由于SU-8波导层与石英基片温度系数的相反极性特性,SU-8膜厚直接影响到了乐甫波器件的温度特性。实验发现,覆盖不同膜厚的SU-8的乐甫波器件的中心频率随温度呈非线性变化,且在60~80℃内,SU-8膜厚为0.95μm时,其频率温度系数约为0.830×10^-6/℃。

This paper experimentally investigated the temperature characteristics of Love wave devices on ST-90°Xquartz/SU-8structure.The electrode width controlled single phase unidirectional distributed transducer（EWC/SPUDT）technique was used for the device design and the 150 MHz SH-SAW delay line devices with Al metallization were fabricated with single-mode feature and low insertion loss.Series of Love wave devices were developed using SU-8guiding layer.Since the SU-8guiding layer and ST-90°Xquartz have complementary temperature coefficient of frequency（TCF）,the thickness of SU-8film significantly affects the temperature characteristics of Love wave devices.The experimental results showed that the non-linear temperature characteristics of Love wave devices,and TCF was observed and the temperature coefficient of frequency（TCF）was about 0.830×10^-6/℃ with the film thickness of 0.95μm from temperature of 60℃to 80℃.The proposed Love wave devices showed a good prospect for physical or chemical sensors in the high temperature using the Love wave device developed in this paper.