Efficiency modeling of a CMOS MEMS convective accelerometer

This paper reports efficiency modeling using 3D FEM simulation of a convective accelerometer obtained by FSBM of a die fabricated using standard CMOS technology. In such sensors, best sensitivity is obtained by placing temperature detectors where air temperature is the most sensitive to acceleration. This will obviously depends on 3D effects. In a previous work, a behavioral model of the sensor including only 2D effects was developed. This work investigates 3D effects which give the opportunity to better predict not only sensor sensitivity but also power dissipation. Experimental sensitivity values and 3D FEM ones are verified for two different sensors and two different heater temperatures. For a prototype having a heater-cavity border distance of 340μm and a heater length of 230μm, maximum sensitivity point is obtained for detectors localized at a distance of 125μm from heater center. Using this 3D geometry in FEM simulations, we show that electrical power decreases more rapidly than sensitivity when heater length is reduced. Moreover, when detectors are shortened, the sensitivity will be quite higher with an optimal value obtained for a detector implemented on one third of the side bridge.

[1]  Pascal Nouet,et al.  Experimental and finite-element study of convective accelerometer on CMOS , 2005 .

[2]  Mona E. Zaghloul,et al.  Micromachined convective accelerometers in standard integrated circuits technology , 2000 .

[3]  B. Mezghani,et al.  From 2D to 3D FEM simulations of a CMOS MEMS convective accelerometer , 2011, ICM 2011 Proceeding.

[4]  Y. J. Yang,et al.  Study on linearity of a micromachined convective accelerometer , 2003 .

[5]  Pascal Nouet,et al.  A MEMS Convective Accelerometer Equipped with On-Chip Facilities for Sensitivity Electrical Calibration , 2011, 2011 IEEE 17th International Mixed-Signals, Sensors and Systems Test Workshop.

[6]  A. Vimalajuliet,et al.  Design of MEMS based capacitive accelerometer , 2010, 2010 International Conference on Mechanical and Electrical Technology.

[7]  Pascal Nouet,et al.  HDL modeling of convective accelerometers for system design and optimization , 2008 .

[8]  Walter Lang,et al.  Micromachined inclinometer with high sensitivity and very good stability , 2002 .

[9]  C N Riviere,et al.  Placement of Accelerometers for High Sensing Resolution in Micromanipulation. , 2011, Sensors and actuators. A, Physical.

[10]  Pascal Nouet,et al.  Modeling and system-level simulation of a CMOS convective accelerometer , 2007 .

[11]  A. A. Rekik,et al.  Modeling the influence of etching defects on the sensitivity of MEMS convective accelerometers , 2010, 2010 IEEE 16th International Mixed-Signals, Sensors and Systems Test Workshop (IMS3TW).