Modeling of a CMOS Capacitive Relative Humidity Sensor

A capacitive relative humidity sensor compatible with CMOS technology is researched. It uses comb electrodes and polyimide as moisture sensing material. A theoretical model for the variation of relative humidity sensor capacitance due to the dielectric constant change of the sensitive layer is built. The sensor is simulated by Ansys software using the same parameters. The conclusions show that the computing results of the theoretical model are in agreement with the simulating results by FEM software. So the model can make for capacitive relative humidity sensors design and fabrication.