This paper investigates design, fabrication and testing of a monolithic piezoresistive flow sensor with on-chip signal conditioning circuit. Post-CMOS Processing of this flow sensor will be the focus of this paper, starting from theoretical analysis and numerical simulation, and moving to experimental verification. The flow sensor presented here is comprised of four symmetrically arranged silicon diaphragms with piezoresistors on them used to sense the drag force induced by the input gas flow. Piezoresistor fabrication has been merged into a conventional CMOS process and releasing of sensing part is conducted after CMOS processing. An integrated flow sensor with on-chip CMOS circuitry fabricated using this novel post-CMOS process was fabricated and tested. The integration method shows good compatibility of MEMS process with the state of art CMOS process. A quadratic relation between output voltage and flow rate was obtained within flow rate of 0-5L/min and the testing result was then compared with an Inter-CMOS based flow sensor. © 2012 The Authors. Published by Elsevier Ltd.
Li, D., Yang, F., Zhao, D., Li, T., & Zhang, D. (2012). Monolithic integration of a micromachined flow sensor based on post-CMOS. In Procedia Engineering (Vol. 47, pp. 1009–1012). Elsevier Ltd. https://doi.org/10.1016/j.proeng.2012.09.318