基于高压应力的氮化铝MEMS压电微扬声器  

AlN MEMS Microspeakers with High Compressive Stress

作　　者：于媛媛 王浩然 张代化[1] 谢会开[2] YU Yuanyuan 1,WANG Haoran 2,ZHANG Daihua 1＊ ,XIE Huikai 2(1.State Key Laboratory of Precision Measuring Technology and Instruments,Tianjin University,Tianjin 300072,China;2.Department of Electrical and Computer Engineering,University of Florida,Gainesville,FL 32611,US)

机构地区：[1]天津大学精密仪器与光电子工程学院,天津300072 [2]佛罗里达大学电气与计算机工程系,美国32611

出　　处：《传感技术学报》2018年第8期1141-1146,1175,共7页Chinese Journal of Sensors and Actuators

摘　　要：基于微电子和微机械加工工艺制备了一类氮化铝AlN(Aluminum Nitride)压电微扬声器。研究了器件薄膜残余应力对器件性能的影响,采用带有高残余压应力的高c-轴取向氮化铝薄膜分别作为器件压电层和支撑层增大微扬声器的输出声压,同时利用工艺手段控制整体薄膜残余应力进一步增大器件输出声压。该微扬声器的悬膜直径仅为1.35 mm,厚度为0.95μm。在开放空间内,采用声压级检测仪对该微扬声器的输出声压级SPL(Sound Pressure Level)进行扫频测试(频率范围:0.5kHz～20 kHz)。测得单个微扬声器在距离为10 mm处,20 Vpp驱动电压下最大输出声压级约为75 dB。测试结果显示该氮化铝压电微扬声器在耳机、智能手机和可穿戴设备等方面都具有潜在的应用前景。A piezoelectric micromachined micospeaker with highly c-axis oriented AlN（Aluminium Nitride）thin films was fabricated by a CMOS-compatible fabrication process.The effects of residual stress on device performance were investigated and two AlN thin films were deposited with heavily compress stress as the piezoelectric and supporting layer to enhance the sound pressure output of the microspeaker,the total residual stress of the diaphragm structure were controlled by a simple,robust fabrication process to give more deflection of the diaphragm.The diameter of the microspeaker is only 1.35 mm and thickness is 0.95μm.The sound pressure level（SPL）has been measured with a variation of sinusoidal input frequency from 0.5 kHz to 20 kHz.The largest SPL of this microspeaker was about 75 dB at 20 Vpeak-to-peak,which was test at the distance of 10 mm from the microspeaker in open field.The results show its potential for the application in earphone,wearable devices and Internet of things（IoT）.

关 键 词：压电微扬声器 氮化铝薄膜 残余应力 输出声压级 

分 类 号：TP212.9[自动化与计算机技术—检测技术与自动化装置]