Micromechanical relative humidity sensor based on epitaxial silicon cantilevers

The paper reports a surface micro-machined relative humidity senor base on a silicon epitaxial process. The sensitive structure was fabricated by a single crystal silicon layer so that excellent mechanical and electronic performances of the device were achieved. To optimize the performances of the sensor, an FEM method was used to evaluate the mechanical responses of the structures. A readout circuit and a test system were designed to evaluate the performances of the relative humidity sensor. According to the test results the sensitivity and hysteresis of the relative humidity sensor is 2mV/%RH and 3%RH respectively. The response time of the humidity senor is 65s.