Intrinsic thermal behaviour of capacitive pressure sensors: mechanisms and minimisation

The thermal behaviour of capacitive pressure sensors fabricated using silicon and Pyrex wafers is analysed by combining the three-dimensional (3D) numerical modelling and the observation of a family of sensors. It is shown that the main mechanism of the capacitance thermal variations is structural deformation. In order to minimise the temperature coefficient, the wafer thickness must be optimised and the bonding area widened.