标题: | 具有可变电感的CMOS MEMS三轴加速度计 Tri-axis CMOS MEMS Accelerometer With Variable Inductors |
作者: | 张岂铭 洪浩乔 邱一 Chang, Chi-Ming Hong, Hao-Chiao Chiu, Yi 电控工程研究所 |
关键字: | 可变电感;加速度计;LC振荡器;Variable inductors;Accelerometer;LC tank Oscillator |
公开日期: | 2016 |
摘要: | 本论文使用CMOS-MEMS制程设计出具有可变电感的三轴加速度计,并将三轴的感测制作于单一质量块上。不同于容易受残余应力影响的电容式加速度计,我们直接使用弹簧来当作可变电感并搭配固定的MIM电容组成一个LC振荡器,当晶片受到一加速度时,弹簧会因为质量块的牵引而发生弹簧线圈面积的改变并产生电感值的变化,同时LC振荡器的输出频率也会跟着改变,而振荡器的频率变化会跟加速度成正比,故可以利用输出频率的变化来侦测加速度大小。 本篇论文设计的晶片有两颗,Sample I与Sample II皆使用1P6M 0.18 um制程。Sample I的机械共振频率在出平面方向为8.28 kHz(Q值3.45),水平面方向为19.2 kHz;而Sample II的X、Y与Z共振频率分别为6.49 kHz(Q值216)、6.56 kHz(Q值218)与6.418 kHz(Q值210)。结合电性量测后得到Sample I的Z轴灵敏度为25.66 KHz/grms @1 grms - 3.5 grms;Sample II的X、Y与Z轴灵敏度分为37.1 KHz/grms、61.2 KHz/grms @0 grms - 5 grms与3.32 KHz/grms @1 grms - 4 grms。 This thesis proposes two tri-axis CMOS-MEMS accelerometers with variable inductors and combine them into a single proof-mass for each. Different from the capacitive accelerometer sensitive to thin-film residual stress, using spring as a variable inductor can prevent from it. The proposed accelerometers use variable inductors and MIM capacitors to form LC oscillators as the capacitors are independent from acceleration. Due to the force and displacement of the proof-mass caused by external acceleration, the coil area of the spring inductors are changed as well as the inductances, and frequencies of LC oscillators are also changed. The frequency deviations in LC oscillators are proportional to the external acceleration. As a result, the sensing method is feasible for detecting the acceleration. Two devices including Sample I and Sample II which has been designed were both fabricated using TSMC 1P6M 0.18 um process in this thesis. The measured mechanical resonant frequencies of Sample I is 8.28 kHz for out-of-plane axis (Q is 3.45) and 19.2 kHz for in-plane axis; another one, Sample II is 6.49 kHz for the X-axis(Q is 216)、6.56 kHz for the Y-axis(Q is 218) and 6.418 kHz for the Z-axis(Q is 210). The measurement results combining with electrical characteristics show that Sample I can achieve 25.66 KHz/grms @1 grms - 3.5 grms for Z-axis;Sample II can achieve 37.1 KHz/grms、61.2 KHz/grms @0 grms - 5 grms and 3.32 KHz/grms @1 grms - 4 grms for X、Y and Z-axis respectively. |
URI: | http://etd.lib.nctu.edu.tw/cdrfb3/record/nctu/#GT070260056 http://hdl.handle.net/11536/140033 |
显示于类别: | Thesis |