CMOS-MEMS Capacitive Humidity Sensor

This paper reports a method for improving the sensitivity of integrated capacitive chemical sensors by removing the underlying substrate. The sensor is integrated with CMOS testing electronics using mask-less post-processing followed by inkjet deposition of sensitive polymer. This technique is demonstrated with a humidity sensor but could be used for other types of analytes. The measured sensitivity is 0.18% change in capacitance per percent relative humidity, a factor of four improvement over previous integrated capacitive sensors.