Title :
The long term reliability of a switched-capacitor relative humidity sensor system
Author :
Denton, Denice D. ; Jaafar, Maha A S ; Ralston, Andrew R K
Author_Institution :
Dept. of Electr. & Comput. Eng., Wisconsin Univ., Madison, WI, USA
Abstract :
The authors investigated the reliability of a solid-state relative humidity (RH) sensor system. The sensor was a 15 pF parallel plate capacitor that employed polyimide as the dielectric. The integrated driving circuit was based on a charge sharing technique. The frequency response, hysteresis, dielectric stability, and long term reliability for the sensor system were determined experimentally. The experimental results indicated that the sensor device capacitance-RH characteristic change when aged at 85°C and 85% RH. The capacitance values at the lowest frequencies and highest ambient RH were affected the most by aging. The performance of the CMOS measuring circuit was not affected when aged at 85°C and 85% RH for a period of 390 h. The effects of change in the aged sensor device on the system output signal were determined. Suggestions are made for maximizing the system stability
Keywords :
CMOS integrated circuits; ageing; electric sensing devices; humidity measurement; reliability; stability; switched capacitor networks; 15 pF; 390 h; 85 C; CMOS measuring circuit; aged sensor device; aging; capacitance-RH characteristic change; charge sharing technique; dielectric stability; experimental results; frequency response; hysteresis; integrated driving circuit; long term reliability; parallel plate capacitor; polyimide dielectric; relative humidity sensor system; solid state humidity sensor; switched capacitor humidity sensor; system output signal; system stability; Aging; Capacitive sensors; Capacitors; Circuit stability; Dielectrics; Humidity; Integrated circuit reliability; Polyimides; Sensor systems; Solid state circuits;
Conference_Titel :
Circuits and Systems, 1992. ISCAS '92. Proceedings., 1992 IEEE International Symposium on
Conference_Location :
San Diego, CA
Print_ISBN :
0-7803-0593-0
DOI :
10.1109/ISCAS.1992.230395
