A Capacitive Polyimide Humidity Sensor with Grid-Type Upper Electrode by CMOS Process

Abstract

A grid-type upper electrode capacitive polyimide humidity sensor fabricated by standard CMOS process was reported. The humidity sensor uses polyimide thin film as humidity-sensitive layer, and aluminum as upper electrode and lower electrode. Details of device structure, fabrication process and sensor characteristics such as sensitivity, hysteresis, and response time are discussed. Test results show that the capacitance-RH curves have reasonable linearity in the range of 12% and 92%, the sensitivity is 0.9 pF/RH, and the response time is about 5.5 s.