悬臂梁结构微机械压阻式加速度传感器研究

【作者】 金虎；

【导师】 陆德仁；

【作者基本信息】 中国科学院上海冶金研究所 ， 微电子学与固态电子学， 2000， 硕士

【摘要】 基于微机械加工技术的压阻式加速度传感器是一类很重要的传感器。传感 器的量程最低可到±2g，最高±500g，线性度一般为0.2%至1%，横向效应一 般在1％至3％。小量程加速度传感器在实际中有较为广泛的用途，如汽车ABS 系统、制导系统等都需要高精确度的小量程传感器。低量程高线性的加速度传 感器除可作为加速度传感器外，还可以应用于倾角仪等。 论文的第一章对微机械加工技术、MEMS器件及其应用和微机械加速度传 感器的研究、以及薄膜应力作用的一般规律进行了综述，总结了MEMS技术的 应用前景及微机械压阻式加速度传感器的研究进展。 第二章详细论述具有悬臂梁结构的压阻式加速度传感器芯片的工作原理、 分析计算了器件的静态、动态特性和温度性能，在此基础上确定了结构参数。 并对横向效应和温度效应的补偿进行了理论计算，结果表明此种结构的三种横 向效应中主要是由于质量块（岛）质心偏离梁中平面，沿梁伸展方向 (x向) 惯性力分量产生的弯矩。 第三章详细阐述了压阻式加速度传感器的制作工艺，包括芯片工艺和盖板 工艺。针对工艺中存在的问题进行了分析，为矫正氧化硅薄膜压应力在小量程 悬臂梁结构传感器中造成的梁的挠曲，确定采用淀积氮化硅薄膜的方法。 论文第四章主要研究了氮化硅及二氧化硅复合薄膜的应力作用规律，对在 本器件中利用氮化硅薄膜应力补偿二氧化硅薄膜应力进行了理论和实验研究， 证明复合薄膜对衬底的应力作用，可视为不同薄膜对衬底作用的线性叠加，且 悬臂梁的挠度与梁上薄膜厚度成正比。 在第五章中，主要讨论了器件的测试方案，对器件的动态、静态性能进行 测试，分析了影响器件性能的工艺和设计因素。测试表明，具有悬臂梁结构的 压阻式微机械加速度传感器在量程±1g，线性度优于 0.05％，灵敏度叫～1mV/gV， 阻尼比～0.7，带宽～11OHz。更多还原

【Abstract】 Micromachachined piezoresistive accelerometers based on the MEMStechnology are very important accelerometers The piezoresistive sensor require lowcost and simple signal processing circuitry, and are compeible with lC processing Asrcsult, the cost can be lowered while the sensitivity and the resolution can beimproved The lowest range of sensors is ±2g～500g, nonlinearity 0. 2%～l%,transverse sensitivity fatio l%～3% The low range piezoresistive accelerometersare widely used in movement controlling system and inlnenometor The automobileindustry meets the large need of the accelerometers in recent yearsIn this paper an introduction of the MEMS technology MEMS devices and itsapplication, inner stress analysis in interface between film and wafef, andmicromachined piezoresistive accelerometers were comprehenslvely surveyed inchapter l And the prospect of the MEMS technology and the micromachinedcapacitive accelerometers were studiedIn Chapter 2, the mechanism, static and dynamic characters, thermal charactersof the piezoresistive accelerometer with cantilever beam were studied in detail Aftertheoretical calculation, it can be conclusion that because the center of mass isn’t incentral plane, inertial force will product bending stress in piezoresistance, is the mainsource of transverse sensitivityIn chapter 3, the process of sensors is elaborated, about the sensing element andcover board For correcting the displacement of mass because of inner stress inintetface SiO₂/S1₃, Si₃N₄. film was adoptedThe mechanism and discipllnanan of lnner stress was stUdled 1n chaPtr 4 It wasproved that the inner stress of multi-layers film is the summation of every single-layers film, and the displacement of the mass is proportional linearity to thickness ofevery single filmIn chapter 5, the static and dynamic characters of this sensors was measured andthe factor which affect sensors character was analyzed based on the measurement dataAs result, the piezoresistive accelerometer with cantilever beam with tange±1g,nonlinearity less than 0.05%, sensitivity～1mV/gV damping factor～o.7 and workbandwidth 110Hz show utility value更多还原