Title :
An all-capacitive sensing chip for temperature, absolute pressure, and relative humidity
Author :
DeHennis, A. ; Wise, K.D.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Michigan Univ., Ann Arbor, MI, USA
Abstract :
This paper presents an all-capacitive sensing chip for temperature, absolute pressure, and relative humidity. The temperature sensors are based on a Si/Au bimorph structure contacting a fixed electrode and produce a sensitivity of 14fF//spl deg/C from 20 to 100/spl deg/C. The absolute pressure sensors have a sensitivity of 15fF/Torr and can be combined to span 500-1200Torr. The relative humidity sensor responds with 39fF/%RH from 20-95%RH. The three-transducer chip uses a bulk- and surface- micromachined silicon-on-glass process and combines anodic bonding with silicon/gold eutectic solder to realize vacuum-sealed cavities along with low-impedance (6/spl Omega/) electrical feedthroughs.
Keywords :
capacitive sensors; elemental semiconductors; gold; humidity sensors; instruments; integrated circuit interconnections; pressure sensors; pressure transducers; silicon; temperature sensors; 20 to 100 degC; 500 to 1200 torr; Si-Au; Si-Au bimorph structure; anodic bonding; capacitive sensing chip; low-impedance electrical feedthroughs; pressure sensors; relative humidity sensor; sensitivity; silicon-gold eutectic solder; surface- micromachined silicon-on-glass process; temperature sensors; transducer chip; vacuum-sealed cavities; Computerized monitoring; Glass; Humidity; Microcontrollers; Sensor phenomena and characterization; Silicon; Temperature sensors; Transducers; Wafer bonding; Wireless sensor networks;
Conference_Titel :
TRANSDUCERS, Solid-State Sensors, Actuators and Microsystems, 12th International Conference on, 2003
Conference_Location :
Boston, MA, USA
Print_ISBN :
0-7803-7731-1
DOI :
10.1109/SENSOR.2003.1217151
