Pressure measurement using hysteresis effects in cantilever microstructures

• Published in: Canadian journal of electrical and computer engineering Vol. 25; no. 1; pp. 43 - 47
• Main Authors: Ma Y, Lawson, Ron P, Brown, K B, Garcia, A, Vermeulen, F E, Robinson, A M, Allegretto, W
• Format: Journal Article
• Language: English
• Published: Montreal The Institute of Electrical and Electronics Engineers, Inc. (IEEE) 01-01-2000
• Subjects: Microtechnology; Pressure (Physics)
• ISSN: 0840-8688

Hysteresis effects are observed as the resonance characteristics of an oscillating microcantilever are modified by changes in ambient air pressure. These effects, which occur for large device deflections, manifest themselves as resonant frequencies and deflection amplitudes whose values depend on whether the actuating frequency is increasing or decreasing. Hysteresis-induced changes in resonant frequency and amplitude of deflection have been measured for pressures ranging from 100 to 0.001 torr. Cantilever-in-cantilever (CIC) devices are damped, driven harmonic oscillators. The damping is due to both the internal structural effects and the properties of the external medium in which the structure oscillates. Previously, CICs have demonstrated the ability to accurately measure pressures between 1500 and 100 torr without hysteresis effects. Measuring the degree of hysteresis for pressures below 100 torr has increased the range of these pressure sensors from better than one order of magnitude to as much as five orders of magnitude (1500 to 0.01 torr).