Sensitivity Analysis of a Micro Pressure Sensor Having Thin Film Diaphragm

Abstract

A theoretical expression to calculate the strain on a circular diaphragm fixed at the circumference and the center has been derived to predict the sensitivity of a micro-diaphragm pressure sensor. Young's modulus and internal stress of several thin films used for the diaphragm of the sensor and their layered structures were measured. Using the measured data, it was confirmed that Young's modulus and internal stress for layered thin film structure can be calculated by a composite law. Two sensors were fabricated to verify the validity of the derived equations, and their sensitivity was measured and calculated. The measured and calculated sensitivities showed good agreement.