倾斜梳齿的MEMS电容式加速度传感器自我标定特性研究  

Study of Self-Calibration of MEMS Capacitive Accelerometer with Non-Parallel Combs

作　　者：董林玺[1] 楼进峰 

机构地区：[1]杭州电子科技大学射频电路与系统教育部重点实验室,杭州310018

出　　处：《传感技术学报》2013年第10期1357-1363,共7页Chinese Journal of Sensors and Actuators

基　　金：国家自然科学基金项目(60506015);浙江省自然科学基金项目(Y107105);GHz频率机械耦合阵列组合的盘结构电容式微机械谐振器关键技术研究项目(61376117);规模集成振动微机械谐振器的静电调谐技术研究项目(LY13F040004)

摘　　要：研究MEMS电容式加速度传感器的自我标定方法,模拟机械振动台标定,提高标定效率和降低标定成本,并从理论上分析了DRIE工艺误差对传感器自我标定精度的影响。分析的传感器模型梳齿间距为4μm,厚度80μm,传感器自我标定以模拟幅值为1 g的振动台标定为例,针对DRIE工艺加工的高深宽比梳齿电容存在正负侧壁倾斜角α的情况,分析了该倾斜角对梳齿式传感器自我标定的影响。分析结果表明：传感器工作在开环电路时,梳齿的倾斜对传感器自我标定影响明显,且随着倾斜角度的增大而增大。与梳齿完全平行时传感器的自我标定相比,倾斜角为＆#177;0.1＆#176;时,自我标定误差约为10%；倾斜角为0.5＆#176;时,自我标定误差约为27%；倾斜角为-0.5＆#176;时,极板发生吸合。表明传感器工作在开环电路时,梳齿的倾斜角对传感器的自我标定影响明显,而传感器工作在闭环电路时,梳齿的倾斜对自我标定的影响明显降低,当倾斜角小于＆#177;0.5＆#176;时,自我标定的误差小于0.6%,理论误差接近于激光干涉仪绝对标定法的误差（0.5%~1%）,证明了自我标定方法的可行性。还分析了倾斜角影响自我标定精度的原因以及提出了开环自我标定时减小倾斜角误差的方法,并阐述了具体的修正步骤。This paper studies the self-calibration of MEMS capacitive accelerometer to simulate the vibrator to increase the efficiency and reduce the cost of calibration,and analyses the effect of DRIE fabrication error on self-calibration of sensors theoretically. The gap of the sensor used in this paper is 4 μm,and the thickness is 80 μm. The self-calibration of sensors simulates the calibration of mechanical vibrator which is vibrating at an amplitude of 1 gn. As the combs of the capacitive sensors fabricated by deep reactive ion etching（DRIE）exist plus-minus slope angle α,this paper analyses the effect of the slope angle on the self-calibration of MEMS capacitive accelerometer. The results show that the error caused by slope angle is obvious,which gets more obvious with bigger slope angle in open loop circuit. Comparing with the self-calibration of parallel comb sensors,the error of self-calibration is about 10% when the slope angle is ＆#177;0. 1＆#176;;27% when the slope angle is 0. 5＆#176;;and pull-in occurs when the slope angle is-0. 5＆#176;. It proves that in open-loop circuit,the slope angle affacts the self-calibration obviously. But the error gets much lower when sensor is in close loop circuit. When the slope angle is less then＆#177;0. 5＆#176;,the error of self-calibration is less than 0. 6%,which is close to the error of the absolute calibration of Laser Interferometer（0. 5% ~1%）,and proves that the method of self-calibration is practicable. Meanwhile,this paper analyses the reasons how slope angle affact self-calibration,and come up with an idea which can lower the error of self-calibration that caused of slope angle in open loop circuit and state the specific measure.

关 键 词：电容式加速度传感器 自我标定 正负侧壁倾斜角 

分 类 号：TP212.1[自动化与计算机技术—检测技术与自动化装置]