Design and fabrication of a low-cost microengineered silicon pressure sensor with linearised output

The design and fabrication of a capacitive pressure sensor comprising two microengineered silicon wafers fusion-bonded together to provide a relatively low-cost pressure sensor is described. The sensor produces a capacitance change of around 100 pF for an applied pressure of eight bar. The capacitance change is measured using a charge redistribution technique. The sensor has been designed to enable subsequent linearisation within a microcontroller. The same microcontroller is also used to calibrate the device, implement a successive approximation register within the charge redistribution circuit, and drive an LCD resulting in an elegant and potentially low-cost system