Characterization of Gas Conductance of a Thermal Device With a V-Groove Cavity

The gas conductance of a V-groove thermal sensor is characterized by the simulation of effective collisions inside the cavity and further verified by the measurements of frequency responses in vacuum and in air. The effective gap depths of a polysilicon microbolometer with an active area of 44 μm × 27 μm and a V-groove cavity of 48 μm × 45 μm were estimated as 4.37 and 4.24 μm by the respective calculations based on the simulation and measurement results which are much lower than those calculated by early models of published papers. The gas conductance of the sensor in atmosphere was further evaluated as 1.4 × 10^-5 W/K which dominates the heat loss of the thermal sensor.