ZnO/SiO_(2)/Si复合结构的声表面波器件特性分析

Characteristics Analysis of Surface Acoustic Wave Devices with ZnO/SiO_(2)/Si Composite Structure

为研究ZnO/SiO_(2)/Si复合结构声表面波器件激发瑞利波的特性,通过有限元方法对该复合结构进行三维建模仿真,得到该结构SAW器件所激励的瑞利波特性,以及其位移-频率、导纳-频率特性曲线。为验证有限元仿真结果的正确性,制备了有无反射栅结构的两组SAW器件。采用等离子体增强化学气相沉积法(PECVD)在Si衬底上制备SiO_(2)薄膜,再采用电子束蒸发镀膜制备ZnO薄膜和金属电极。实验利用矢量网络分析仪对两组器件进行了测试,测得两组SAW器件的谐振频率均与仿真结果相近,有反射栅的SAW器件比无反射栅的SAW器件在谐振频率处S_(11)增大了8.1 dB。结果表明:实验制备的SAW器件特性与仿真结果具有较好的一致性,SAW器件的反射栅的存在增强了回波信号,验证了反射栅的反射特性。

This paper obtained the characteristics of the Rayleigh wave excited by ZnO/SiO_(2)/Si composite structure surface acoustic wave device,and the characteristic curves of its displacement-frequency and admittance-frequency by three-dimensional modeling and simulation based on finite element method.To verify the correctness of the finite element simulation results,two sets of SAW devices with or without reflective gate structure were fabricated.Plasma-enhanced chemical vapor deposition(PECVD)was used to prepare SiO_(2)film on Si substrate,and then electron beam evaporation coating was used to prepare ZnO film and metal electrode.The vector network analyzer was utilized to test the two sets of devices,and the measured resonant frequencies of the two sets of SAW devices were similar to the simulation results,and the S_(11)at the resonant frequency of the SAW device with reflector was 8.1 dB larger than that of the SAW device without reflector.The results show that the characteristics of the SAW devices fabricated by the experiment are in good line with the simulation results,and the reflector of the SAW device enhances the echo signal and verifies the reflection characteristics of the reflection grid.