Thermal simulation of micromachined bridge and self-heating for uncooled VO2 infrared microbolometer

Since the response of microbolometer detectors depends on the modification of temperature in micromachined bridge structures, it is useful to model and simulate thermally the corresponding structures in order to predict their performance parameters. By a finite element analysis, the simulation has been performed on the stationary and transient temperature distribution within the unit element of microbolometer. The results can be used to estimate the effect of the structure, pixel size and package on the element temperature change induced by infrared radiation and thermal time constant. The influence of self-heating has been also analyzed. The readout time period for microbolometer should be designed correctly in terms of the self-heating. On the other hand, the non-uniformity distribution of microbolometer element resistance will cause an output voltage drift because of the self-heating effect. The calculation shows that when the element resistance is more than 15 kΩ, the output voltage drift can be almost neglected.