Evaluation of Piezoresistive Property of Vanadium Oxide Thin Film Deposited by Sputtering

This article shows the evaluation of piezpresistive property of a vanadium oxide (VOx) film. The VOx film is deposited by the reactive sputtering method and patterned as a piezoresistor on an edge of suspended silicon (Si) membrane. The VOx resistor, electrode pads connected to the resistor, and the suspended membrane structure are fabricated using conventional microfabrication techniques. The resistance of the VOx resistor changes as the membrane is deflected. The deflection of the membrane is caused by evacuating to each differential pressure (from -0.02 to -0.05 by -0.01 MPa) and measured using a white-light interferometer. The resistance decreases as the strain is increased. The gauge factor of the deposited VOx is 259, which is higher than general semiconductor materials such as Si. The feasibility of VOx as a focusing material for MEMS/NEMS application (e.g., strain gauge) is indicated by our experiment.