Fabrication and Test of MEMS/NEMS based Polyimide Integrated Humidity, Temperature and Pressure Sensor

MEMS/NEMS based integrated sensors for humidity, temperature and pressure used in environment monitoring are usually combined by separate devices for complicated technology and material compatibility. In order to lower cost, polyimide (PI) was introduced in to fabricate integrated sensors realizing IC compatible process. Different humidity electrodes have been investigated and a humidity sensor with a sensitivity of 2.375pF/RH% during 20~90%RH is fabricated. Performance in high humidity is compensated by temperature elements, which shows excellent linearity from -20degC to 100degC. Polyimide and nitride diaphragm was used to measure external pressure, which achieves a sensitivity of 1.1 mV/degC and an accuracy of 0.06 kPa.