Microfabricated Implantable Pressure Sensor for Flow Measurement

摘要

A RF wireless capacitive pressure sensor is developed. The sensor has integrated inductor with the pressure sensitive capacitor as LC circuit. The resonant frequency of the sensor changes as the capacitance changes with applied pressure. The sensor uses LPCVD silicon nitride as sensitive membrane and the residual stress of the membrane has been measure as 139MPa. The sensor has size of 10 mm × 4 mm ×0.5 um. The sensor presents a pressure sensitivity of 1.65 MHz/cmH_2O in pressure range of 0-20 cmH_2O. The deflection of different shape of membranes is discussed. The deflection of square membrane is 130% to circular membrane under same applied pressure.