CMOS集成电容湿度传感器

Integrated Capacitive Humidity Sensor by CMOS IC Technology

CMOS集成湿度传感器是利用MEMS技术基于CMOS工艺的新型传感器,将传感器结构与接口电路集成在同一块片子上,具有体积小,价廉、可靠性高等优点,利于批量生产和系统集成。主要介绍了湿度传感器的工作原理和一些常用感湿介质,如多孔硅、聚酰亚胺、空气的感温特性,比较了几种流行的湿度传感器结构以及接口信号处理电路像开关电容电路、多谐振荡电路之间的优缺点。最后给出了微系统集成的概念,并对CMOS集成湿度传感器的应用前景进行了展望。

Integrated capacitive humidity sensors are novel sensors based on standard CMOS IC process and MEMS technology. This kind of humidity sensors integrate the structure of the sensors and interface circuits on a chip. The miniature volume, the low price and long - term reliability are the advantages of the relative humidity (RH) sensors. It is suitable to batch - processing and integrated system because of miniature volume. The sensing principle of the sensor is the dielectric constant change of humidity sensing material due to absorption/desorption of water. This paper introduces several popular humidity - sensitive materials, such as porous silicon (PS) , polyimide (PI) and air. Some common structure of humidity sensors and interface circuits are presented here. The on-chip calibration circuits are based on the switched - capacitor and multivibrator circuits. The characteristics between different structures and interface circuits are reported. The paper summarizes major technological approaches to CMOS - based microsensors. Finally the concept of integrated microsystems is discussed. Prospective applications are predicted.