Title :
Surface-micromachined capacitive differential pressure sensor with lithographically defined silicon diaphragm
Author :
Mastrangelo, Carlos H. ; Zhang, Xia ; Tang, William C.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Michigan Univ., Ann Arbor, MI, USA
fDate :
6/1/1996 12:00:00 AM
Abstract :
A capacitive surface-micromachined sensor suitable for the measurement of liquid and gas pressures was fabricated. The structure consists of a polysilicon stationary electrode suspended 0.7 μm above a 20-μm-thick lightly doped silicon diaphragm formed by a patterned etch stop. The a priori patterning of the buried etch stop yields diaphragm widths independent of wafer thickness variations with excellent alignment. The design described here has a pressure range of 100 PSI, a nominal capacitance of 3.5 pF with a full scale span of 0.8 pF, and a temperature coefficient of 100 ppm°C-1. Each device, including a matched reference capacitor, occupies 2.9 mm2 , yielding approximately 2000 devices per 100-mm wafer
Keywords :
electric sensing devices; elemental semiconductors; etching; lithography; microsensors; pressure measurement; pressure sensors; semiconductor device testing; semiconductor technology; silicon; 0.7 mum; 100 psi; 20 mum; 3.5 pF; Si; Si diaphragm; Si lithographically defined diaphragm; buried etch stop; gas pressures; liquid pressures; matched reference capacitor; patterned etch stop; polysilicon stationary electrode; surface-micromachined capacitive differential pressure sensor; Calibration; Capacitive sensors; Capacitors; Electrodes; Etching; Gas detectors; Pressure measurement; Reproducibility of results; Sensor phenomena and characterization; Silicon;
Journal_Title :
Microelectromechanical Systems, Journal of
