双层SiO_2薄膜对ZnO/Si结构瑞利波器件性能的改善  

Improvement of Performance of Rayleigh Wave Device With ZnO/Si Structure by Double SiO_2 Layers

作　　者：王艳[1] 徐旬 贾之杰 刘小庆 徐静 WANG Yan;XU Xun;JIA Zhijie;LIU Xiaoqing;XU Jing(College of Electronic and Optical Engineering,Nanjing University of Posts and Telecommunications,Nanjing 210046,China)

机构地区：[1]南京邮电大学电子与光学工程学院,江苏南京210046

出　　处：《压电与声光》2018年第6期818-821,共4页Piezoelectrics & Acoustooptics

基　　金：国家自然科学基金资助项目(11304160);南京邮电大学基金资助项目(NY213018)

摘　　要：利用3D有限元法分析了SiO_2薄膜对ZnO/IDT/Si结构中瑞利波特性的影响,包括相速度(vp)、机电耦合系数(k2)和频率温度系数(τf)。结果表明,当hZ/λ=0.44时,ZnO/IDT/Si结构激发的瑞利波的机电耦合系数最大值k2max=2.38%,且vp=3 016m/s,τf=-32.94×10-6℃-1。引入底层SiO_2薄膜,即ZnO/IDT/SiO_2/Si结构,瑞利波的机电耦合系数大幅提高,当hZ/λ=0.44,hsb/λ=0.25时,k2max=3.41%,且vp=2 801 m/s,τf=-11.43×10-6℃-1。继续引入顶层SiO_2薄膜,即SiO_2/ZnO/IDT/SiO_2/Si结构,瑞利波相速度得到提高,但机电耦合系数随着SiO_2厚度的增加而减小。当hZ/λ=0.44,hsb/λ=0.25,hst/λ=0.25时,k2=2.61%,vp=3 036m/s,τf=18.44×10-6℃-1。双层SiO_2薄膜的引入提高了ZnO/IDT/Si结构瑞利波器件的相速度、机电耦合系数,实现了温度补偿,因此,该结构可用于高机电耦合系数、高温度稳定性及低成本SAW器件的研制。The effect of SiO2 film on the Rayleigh wave characteristics in ZnO/IDT/Si structure is analyzed by3 D-finite element method(3 D-FEM),including the phase velocity(vp),electro-mechanical coupling coefficient(k2),and temperature coefficient of frequency(τf).The results show that,for the Rayleigh waves excited in ZnO/IDT/Si structures,the maximumk2 of 2.38%is obtained as hZ/λ=0.44,associated with vpof 3 016 m/s andτfof-32.94×10-6℃-1.The k2 values of Rayleigh waves in ZnO/IDT/SiO2/Si structures are increased significantly by introducing the bottom SiO2 layer.As hZ/λ=0.44 and hsb/λ=0.25,the coupling coefficient k2 maxequals to 3.41%,with vpandτfof 2 801 m/s and-11.43×10-6℃-1,respectively.For the Rayleigh wave devices based on ZnO/IDT/SiO2/Si structures,the introducing of top SiO2 layer results in the increasing of phase velocity,while the decreasing of the coupling coefficient with the increase of the thickness of SiO2.And the k2 of 2.61%is obtained as hZ/λ=0.44,hsb/λ=0.25 and hst/λ=0.25,associated with vpof 3 036 m/s andτfof 18.44×10-6℃-1.All of the results indicate that the introducing of double SiO2 layers can effectively increase the phase velocity,electro-mechanical coupling coefficient and realize the temperature compensation of the Rayleigh wave devices.Thus the proposed structure can be used to develop SAW device with high electro-mechanical coupling coefficient,high temperature stability and low cost.

关 键 词：3D有限元仿真 ZNO薄膜 SIO2薄膜 瑞利波器件 

分 类 号：TN65[电子电信—电路与系统]