Integrated FET Micro-Humidity Sensors with readout circuit

• Main Authors: Chung-Lan Huang, 黃鍾嵐
• Other Authors: 戴慶良
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/01464235547188979116

碩士 === 中興大學 === 機械工程學系所 === 95 === The MOSFET (metal oxide semiconductor field effect transistor) micro humidity sensors are manufactured by TSMC 0.35 μm CMOS(complementary metal oxide semiconductor). This study is different from the capacitive or resistant humidity sensors. The MOSFET humidity sensors includes sensing MOS﹐circuits, temperature sensors and sensing film. The sensing MOS generates a change in current when supplying a voltage to the gate of sensing MOS. The length and width of gate in the sensing MOS are 4 μm and 100 μm, respectively. In order to increase the current variation the humidity sensors are designed as an array of sensing MOS. The sensing film is sensitive to vapor water, which it is prepared by the sol-gel process and calcined at 300℃ for 4 hours. In this way﹐we can effectly decrease the cost. The temperature sensors is designed using the polysilicon layer of the CMOS process. The temperature sensors have a change in resistance as the temperature varies. A circuit is used to convert the current variation into the output voltage. Experimental results show that the sensitivity of the sensor is 7.5mV/ %RH at 25℃ under the humidity range of 25-85 % RH.