Analyzing thermal conductance measurements in microbolometers

Thermal conductance is a controlling parameter for heat transfer in microbolometer based infrared imaging systems. The thermal conductance can be measured by monitoring the microbolometer temperature change induced by a known electrical power excitation due to constant voltage or current Joule heating at thermal equilibrium. The temperature change is calculated from the corresponding resistance change by using the conduction mechanism for the microbolometer thermosensitive material. For amorphous semiconductor materials, such as VOx and amorphous silicon, electrical conduction is by Variable Range Hopping (VRH), specifically, Efros-Shklovskii VRH for VOx, and Mott VRH for amorphous silicon. Calculation results are compared to published thermal conductance measurements based on linear approximations of the electrical conductivity temperature dependence.