Gas Flow Sensing with a Piezoresistive Micro-Cantilever

This study exploits a bending-up cantilever caused by residual stress to manufacture a micro gas flow sensor. MEMS techniques are used to deposit a silicon nitride layer on a silicon wafer to create a piezoresistive structure. A platinum layer is deposited on the silicon nitride layer to form a resistor and the structure is then etched to form a freestanding micro-cantilever. When an airflow passes over the cantilever beam, a deformation of the resistor occurs. Variations in the airflow velocity are then determined by measuring the corresponding change in the resistance using an LCR meter. The experimental data indicate that the proposed gas flow sensor has a high sensitivity (0.0533 Omega/ms^-1) and a high measurement limit (45 ms^-1).