Tunable pressure sensing applications of a MEMS buckled membrane

Abstract

Buckled membranes are commonly used in microelectromechanical systems (MEMS) structures. One application of a microfabricated membrane is pressure sensing. A differential pressure across the membrane causes deflection, up or down, which can be measured and related to a specific pressure change. Recent work has demonstrated that the deflection and stiffness of these membranes can be tuned through localized joule heating. This opens up a wider range of possible applications of these membranes. In typical pressure sensor design, the mechanical properties of the membrane are constant resulting in a limited range of response to pressure. By tuning the stiffness of the membrane, its pressure response is varied providing a wider range of application for the pressure sensor. A 1.5mm by 1.5mm square membrane demonstrated a decrease in pressure sensitivity from 6μm/psi to 0.2μm/psi over a range of 0 to 15 volts applied to an electrothermal heater on top of the membrane.