CMOS MEMS Thermal Flow Sensor With Enhanced Sensitivity for Heating, Ventilation, and Air Conditioning Application

• Published in: IEEE transactions on industrial electronics (1982) 2021-05, Vol.68 (5), p.4468-4476
• Main Authors: Xu, Wei, Wang, Xiaoyi, Wang, Ruijie, Izhar, Xu, Jingcui, Lee, Yi-Kuen
• Format: Article
• Language: English
• Subjects: Air conditioning; Air flow; CMOS; CMOS technology; Complementary metal–oxide–semiconductor (CMOS) microelectromechanical systems (MEMS); HVAC; HVAC equipment; indoor airflow measurement; Indoor environments; Microelectromechanical systems; Micromechanical devices; Packaging; Packaging design; Polysilicon; Power consumption; Sensitivity; Sensitivity enhancement; Sensors; Silicon; Temperature measurement; thermal flow sensor; Thermal sensors; thermoresistive; Ventilation
• ISSN: 0278-0046; 1557-9948
• DOI: 10.1109/TIE.2020.2984446

In this article, by using 0.35- μ m two-polysilicon four-metal CMOS MEMS technology, a thermoresistive micro calorimetric flow (TMCF) sensor with two packaging designs is systematically investigated: Open-space (O-type) and probe-with-channel (P-type) designs. In comparison with the O-type design, the P-type sensor shows an 80% enhanced sensitivity with a relieved tilt angle effect on the mainstream airflow detection. Accordingly, the P-type packaged flow sensor for HVAC gains a prominent normalized sensitivity ( S* ) of 228 μV/(m/s)/mW, while also having a low power consumption ( P ) of less than 4.2 mW. Moreover, within the linear range of -2 to 2 m/s, an accuracy of ±0.05 m/s is achieved, thus enabling this robust flow sensor (repeatability