A MEMS-based Air Flow Sensor with a Free-standing Micro-cantilever Structure

Abstract

This paper presents a micro-scale air flow sensor based on a free-standing cantilever structure. In the fabrication process, MEMS techniques are used to deposit a silicon nitride layer on a silicon wafer. A platinum layer is deposited on the silicon nitride layer to form a piezoresistor, and the resulting structure is then etched to create a freestanding micro-cantilever. When an air flow passes over the surface of the cantilever beam, the beam deflects in the downward direction, resulting in a small variation in the resistance of the piezoelectric layer. The air flow velocity is determined by measuring the change in resistance using an external LCR meter. The experimental results indicate that the flow sensor has a high sensitivity (0.0284 Ω/ms-1), a high velocity measurement limit (45 ms-1) and a rapid response time (0.53 s).

Micromachined Flow Sensors in Biomedical Applications

“…, with a response time of about 0.53 s and a power consumption of 0.02 mW, was realized by Wang et al [66]. They upgraded their valuable work by integrating temperature compensation and the ability to discriminate flow direction [67], as shown in Figure 3.…”

Fabrication, characterization, and simulation of a cantilever-based airflow sensor integrated with optical fiber

“…Flow sensing by microelectromechanical system (MEMS) technologies, have many advantages compared with their conventional large-scale counterparts, such as anemometers, turbines, Pitot tubes, and so forth [1][2][3][4][5][6][7]. MEMS sensors have many advantages including lower power consumption, higher precision, more rapid response, more improved portability, and lower manufacturing cost [8][9][10][11][12].…”

Tunable Sensor Response by Voltage-Control in Biomimetic Hair Flow Sensors

“…They fabricated artificial hairs using cantilevers with read-out by strain gauges, and demonstrated the measurement of flow velocities up to 2 m/s. Other groups also developed cantilever-based structures with strain gauges for measurement of DC-flows [8], and showed measurements of flow velocities up to 20 m/s [9] and 45 m/s [10]. Sadeghi et al [11] developed artificial hair flow sensor by manually mounting a hair on a hydraulic sensor system, for conversion of angular rotation into capacitive changes, capable of measuring DC-flows up to 10 m/s.…”