基于圆形振动膜的MEMS压电传声器研究
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摘要
为提高微电子机械系统(Micro-electro-mechanical systems,MEMS)压电传声器的灵敏度和成品率,提出一种优化设计的圆形振动膜MEMS压电传声器。采用硼扩散方法实现振动膜的圆形支撑墙,避免由于方形支撑墙造成的四角应力集中,并通过深硼扩散技术,增加圆形围墙的厚度,避免了振动膜的"软"支撑问题;振动膜采用Si3N4/SiO2/Si3N4复合结构,减少振动膜的内应力;采用电极分割串联技术,传声器被分割成在声学上并联、在电学上串联的若干部分,以期提高MEMS传声器的灵敏度。在结构优化的基础上,利用MEMS技术制备压电微传声器,所制备传声器振动膜平坦、无褶皱,成品率有了明显提高。在消声室中采用同时比较法对传声器进行测量,优化设计的圆形振动膜传声器的灵敏度有了明显提高,达到0.3 mV/Pa。
A improved micro-electro-mechanical systems(MEMS) piezoelectric microphone with circular diaphragm is developed to improve the sensitivity and the rate of finished product of microphone.Circular supporting wall of diaphragm is fabricated using boron-doped method to avoid stress concentration at four corners of diaphragm on rectangular supporting wall,and the deep boron-doped technique is adopted to increase the thickness of supporting wall and avert "softer" support for diaphragm;The vibrating diaphragm is composed of Si3N4/SiO2/Si3N4 composite films which reduce internal stress;The microphone is divided into some parts which are acoustical parallel connection and electrical series connection using segmenting electrodes in series method to improve the sensitivity.The microphone is fabricated by micromachined technology after structure optimization and tested by comparison method in anechoic chamber.The vibrating diaphragm is flat without wrinkling and the rate of finished product is higher.The sensitivity of microphone has great increased and achieves about 0.3 mV/Pa.
A improved micro-electro-mechanical systems(MEMS) piezoelectric microphone with circular diaphragm is developed to improve the sensitivity and the rate of finished product of microphone.Circular supporting wall of diaphragm is fabricated using boron-doped method to avoid stress concentration at four corners of diaphragm on rectangular supporting wall,and the deep boron-doped technique is adopted to increase the thickness of supporting wall and avert "softer" support for diaphragm;The vibrating diaphragm is composed of Si3N4/SiO2/Si3N4 composite films which reduce internal stress;The microphone is divided into some parts which are acoustical parallel connection and electrical series connection using segmenting electrodes in series method to improve the sensitivity.The microphone is fabricated by micromachined technology after structure optimization and tested by comparison method in anechoic chamber.The vibrating diaphragm is flat without wrinkling and the rate of finished product is higher.The sensitivity of microphone has great increased and achieves about 0.3 mV/Pa.
引文
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[10]李俊红,汪承灏,徐联.衬底和O2/Ar气体比例对ZnO薄膜结构及性能的影响[J].功能材料,2008,39(1):79-82.LI Junhong,WANG Chenghao,XU Lian.Effect ofsubstrates and O2/Ar gas ratios on the structures andproperties of ZnO films[J].Journal of FunctionalMaterials,2008,39(1):79-82.
[2]马军,郝震宏,徐联,等.MEMS压电水听器的研究[J].声学技术,2007,26(4):296-299.MA Jun,HAO Zhenhong,XU Lian,et al.Study on theMEMS piezoelectric hydrophone[J].Technical Acoustics,2007,26(4):296-299.
[3]CHOI S,LEE H,MOON W.A micro-machinedpiezoelectric hydrophone with hydrostatically balanced airbacking technique[J].Sensors and Actuators A:Physical,2010,158:60-71.
[4]杨楚威,李俊红,黄歆,等.圆形振动膜ZnO压电微传声器研制[J].应用声学,2006,25(4):197-200.YANG Chuwei,LI Junhong,HUANG Xin,et al.Siliconbased ZnO piezoelectric micro-microphone with circularvibrating film[J].Applied Acoustics,2006,25(4):197-200.
[5]LEE W S,KIM Y C,LEE J S,et al.Fabrication ofcircular diaphragm for piezoelectric acoustic devices[C]//Micro Electro Mechanical Systems,2005.MEMS 2005.18th IEEE International Conference,2005:307-310.
[6]LEE W S,LEE S S.Piezoelectric microphone built oncircular diaphragm[J].Sensors and Actuators A:Physical,2008,144:367-373.
[7]潘昕.防粘连硅微传声器的研究[D].北京:中国科学院声学所,2006.PAN Xin.Anti-stiction structure for silicon condensermicrophone[D].Beijing:Institute of Acoustics of ChineseAcademy of Sciences,2006.
[8]刘梦伟.基于PZT薄膜的压电硅微传感器研究[R].北京:中国科学院声学研究所,2009.LIU Mengwei.Piezoelectric microsensors based on PZTthin films[R].Beijing:Institute of Acoustics of ChineseAcademy of Sciences,2009.
[9]杨楚威.硅微压电传声器的研究[D].北京:中国科学院声学研究所,2004.YANG Chuwei.Silicon piezoelectric microphone[D].Beijing:Institute of Acoustics of Chinese Academy ofSciences,2004.
[10]李俊红,汪承灏,徐联.衬底和O2/Ar气体比例对ZnO薄膜结构及性能的影响[J].功能材料,2008,39(1):79-82.LI Junhong,WANG Chenghao,XU Lian.Effect ofsubstrates and O2/Ar gas ratios on the structures andproperties of ZnO films[J].Journal of FunctionalMaterials,2008,39(1):79-82.