Optimisation of CMOS compatible microbolometer device performance

Abstract

Uncooled IR (infrared) microbolometer performance is greatly affected by the thermal properties associated with the structural layout of each design. Equations are derived in this article which make use of basic structural dimensions to predict the expected thermal conductance and thermal capacitance of a microbolometer device. These equations enable a microbolometer designer to determine the estimated thermal time constant of a design without performing complicated analytical calculations for each layer in the design. Calculation results shown indicate the effect structural changes have on the thermal time constant of microbolometer devices. These changes aid microbolometer designers in adjusting the layout of the device to change the thermal time constant to the desired value. Structural deviations that occur during manufacturing of microbolometers are calculated and the possible causes are discussed.