A Novel Simple Humidity Sensor Constructed by Sandwiched Cantilever

This paper presents a novel humidity sensing mechanism. A simple sandwiched cantilever fabricated by traditional MEMS (microelectromechanic systems) process is proposed in this study. During the operation of humidity sensing, the polyimide-sensing layer, top layer of the sandwiched micro-cantilever, swells and the induced compressive stress pushes the tip of cantilever to deflect downward. To systematically investigate the performance of humidity sensor, three items were conducted in this study including response curve, time response, and hysteresis. The simple sensing mechanism had been verified and yielded a high average response time of 0.7 second during humidity range from 65%RH to 95%RH.