设计和工艺参数对声表面波器件性能的影响  

Effects of Design and Process Parameters on Performances of Surface Acoustic Wave Devices

作　　者：胡铭楷 翁昊天 刘骏尘 付学成[1] 史丽云[1] 丁桂甫[1] 张亚非[1] 段力[1] Hu Mingkai Wong Haotian Liu Junchen Fu Xuecheng Shi Liyun Ding Guifu Zhang Yafei Duan Li(The School of Electronic Information and Electrical Engineering （SEIEE）, Shanghai Jiaotong University, Shanghai 200240, Chin)

机构地区：[1]上海交通大学电子信息与电气工程学院,上海200240

出　　处：《微纳电子技术》2017年第11期752-759,共8页Micronanoelectronic Technology

基　　金：国家自然科学基金资助项目(F040801)

摘　　要：设计并制作了多种声表面波(SAW)器件,并研究了设计参数与工艺参数对器件特性的影响。首先在同一块掩膜板内设计了多组不同尺寸与间距参数的SAW器件,然后用微电子机械系统(MEMS)微加工工艺在Mg_xZn_(1-x)O/Si压电薄膜和128°YZ与XZ取向的LiNbO_3压电材料衬底上制作了多种SAW器件。利用X射线衍射(XRD)对压电材料的压电晶向进行了测量、表征和工艺比较,确定了适宜的薄膜溅射条件。利用网络分析仪(VNA)及高频探针台测量了S11高频特性,测量结果表明相对应的谐振频率值与理论值相符合,测出的谐振频率在80~330 MHz。分析了工艺偏差对SAW器件谐振特性的影响。分析结果表明由于工艺偏差导致的叉指电极的指宽差异导致了谐振频率与理想计算值的偏差,工艺偏差同样会导致S11曲线的不对称和谐波的产生。通过LiNbO_3上制作的SAW器件计算出的声波传播速度比较统一,128°YX LiNbO_3上制作的SAW器件计算出的声波传播速度为3 800~3 900 m/s,XZ LiNbO_3上制作的SAW器件计算出的声波传播速度为3 300~3 400 m/s;而在Mg_xZn_(1-x)O/Si压电薄膜上制作的SAW器件推算出的声波传播速度与设计波长或相关尺寸有关。Varieties of surface acoustic wave （SAW） devices were designed and fabricated. The effects of design and process parameters on the device performances were studied. Firstly, several groups of the SAW devices with different sizes and gap distances were designed on the same mask, and then were fabricated on the MgxZnl-xO/Si piezoelectric thin film and LiNbO3 piezo- electric material substrate with 128°YZ orientation and XZ orientation by the micro-electromecha-nical system （MEMS） microfabrication technology. The piezoelectric crystal orientation of the piezoelectric materials were measured, characterized and compared from the process by X-ray dif- fraction （XRD） to determine the suitable sputtering conditions of the thin film. Using a virtual network analyzer （VNA） and high-frequency probe station, the high-frequency characteristics S11 of the SAW devices were measured. The measurement results show that the measured reso- nant frequency is 80 - 330 MHz and nearly consistent with the theoretical corresponding value. The effect of the process deviation on the resonance characteristic of the SAW device was ana- lyzed. The results show that the finger width difference of interdigital electrodes caused by the process deviation results in the deviation between the resonant frequency and ideal calculation value, and the process deviation also lead to the asymmetry of $11 curves and harmonic wave generation. The acoustic velocities calculated by SAW devices on LiNbO3 substrates are relatively uniform, the acoustic velocities calculated by SAW devices on 128°YX LiNbO3 and XZ LiNbO3 substrates are 3 800 - 3 900 m/s and 3 300 - 3 400 m/s, respectively. The acoustic velocity calcu- lated by the SAW device fabricated on MgxZn1-xO/Si piezoelectric thin films is related to design wavelength or relative size.

关 键 词：声表面波(SAW)器件 压电薄膜 射频器件 谐振频率 回波损耗 

分 类 号：TN65[电子电信—电路与系统]