Title :
Contamination insensitive differential capacitive pressure sensors
Author :
Wang, C.C. ; Gogoi, B.P. ; Monk, D.J. ; Mastrangelo, C.H.
Author_Institution :
Dept. of Electr. Eng. & Comput. Sci., Michigan Univ., Ann Arbor, MI, USA
Abstract :
In this paper, a contamination insensitive differential capacitive pressure sensor with a sealed gap is presented. This device is made of three polysilicon layers including a stationary middle plate and the top and bottom plates that are rigidly coupled together by a series of posts and hence deflect in tandem by a change in differential or gauge pressure. Because of the posts, however, the device is insensitive to common mode pressure. As the differential pressure is changed from -80 kPa to 80 kPa, the capacitance between the bottom and middle plates changes by 86 fF, yet there is only a 2 fF change in output when the common mode pressure is applied from 30 kPa to 200 kPa
Keywords :
capacitive sensors; impurities; micromachining; microsensors; pressure sensors; surface contamination; -80 to 80 kPa; Si; contamination insensitive pressure sensors; deflection; differential capacitive pressure sensors; differential pressure; gauge pressure; plates; polysilicon layers; posts; rigid coupling; sealed gap; Capacitance; Capacitive sensors; Capacitors; Couplings; Electrodes; Etching; Silicon; Surface contamination; Tensile stress; Thermal stresses;
Conference_Titel :
Micro Electro Mechanical Systems, 2000. MEMS 2000. The Thirteenth Annual International Conference on
Conference_Location :
Miyazaki
Print_ISBN :
0-7803-5273-4
DOI :
10.1109/MEMSYS.2000.838577
