Micromechanical Gas Heat Capacity Sensor

We report micromechanical thermal sensor with 150 nm thick silicon nitride membrane adapted for gas heat capacity measurements. The operation of the sensor is based on inertial properties of a heated structure including the membrane and an overheated gas. The theoretical predictions are compared with experimental observations. Electronic circuitry intended for modulated heating of the membrane and high resolution readout is described. The sensor is able to measure thermophysical parameters resulting in gas heat capacity changes.