SOI CMOS multi-sensors MEMS chip for aerospace applications

Abstract

In this paper, we report for the first time an SOI CMOS multi-sensors MEMS chip, capable of sensing three key flow parameters i.e. pressure, temperature and flow rate simultaneously. The chip contains an array of ten silicon diode temperature sensors, a piezoresistive pressure sensor and an array of nine micro hot-film flow rate sensors. The chip has been fabricated through a commercial CMOS foundry. The sensors have been embedded in thin oxide membranes that were obtained through a single, post-CMOS DRIE (deep reactive ion etching) back-etch step at the foundry. Characterization of each type of sensor was carried out using independent calibration setups. Temperature sensors exhibited a sensitivity of 1.6 mV/ °C at 1μA constant current in forward bias mode. Pressure sensor showed a sensitivity of 0.4734 mV/V/psi whereas the flow rate sensors showed typical third order calibration curve once operated in constant current mode. The chip can be used in micro-channels for micro-fluidic applications as well as on real aerodynamic surfaces and wind tunnel models for experimental verification of CFD results.