The Design, Development, and Optimization of a Capacitive Pressure Sensor Utilizing an Existing 9 DOF Platform

Authors: Andrew Randles, Ilker Ocak, Cheam Daw Don, Navab Singh, Alex Gu

Abstract:

Nine Degrees of Freedom (9 DOF) systems are already in development in many areas. In this paper, an integrated pressure sensor is proposed that will make use of an already existing monolithic 9 DOF inertial MEMS platform. Capacitive pressure sensors can suffer from limited sensitivity for a given size of membrane. This novel pressure sensor design increases the sensitivity by over 5 times compared to a traditional array of square diaphragms while still fitting within a 2 mm x 2 mm chip and maintaining a fixed static capacitance. The improved design uses one large diaphragm supported by pillars with fixed electrodes placed above the areas of maximum deflection. The design optimization increases the sensitivity from 0.22 fF/kPa to 1.16 fF/kPa. Temperature sensitivity was also examined through simulation.

Keywords: Capacitive pressure sensor, 9 DOF, 10 DOF, sensor, capacitive, inertial measurement unit, IMU, inertial navigation system, INS.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1338396

References:

[1] W. P. Eaton and J. H. Smith. "Micro machined pressure sensors: review and recent developments." In Smart Structures and Materials' 97, 1997, pp. 30-41.
[2] P. Kropelnicki, K. Muckensturm, X. J. Mu, A. B. Randles, H. Cai, W. C. Ang, J. M. Tsai and H. Vogt. “CMOS-compatible ruggedized hightemperature Lamb wave pressure sensor.” Journal of Micromechanics and Micro-engineering, vol. 23, no. 8, 2013, pp. 085018.
[3] I. E. Ocak, D. D. Cheam, S. N. Fernando, A. T. Lin, P. Singh, J. Sharma, G. L. Chua, B. Chen, A.Y.D. Gu, N. Singh, and D. L. Kwong "A monolithic 9 degree of freedom (DOF) capacitive inertial MEMS platform." in Electron Devices Meeting (IEDM), 2014 IEEE International. San Francisco, 2014, pp. 22-6.
[4] M. Hopcroft, W. D. Nix, and T. W. Kenny. "What is the Young's Modulus of Silicon?" Micro-electromechanical Systems, Journal of, vol. 19, no. 2, 2010, pp. 229-238.
[5] M. Narducci, L. Yu-Chia, W. Fang, and J. Tsai. "CMOS MEMS capacitive absolute pressure sensor." Journal of Micromechanics and Micro-engineering, vol. 23, no. 5, 2013, pp. 055007.