Design of a high fill-factor micromachined bolometer for thermal imaging applications

This paper reports a novel design of a microchined bolometer for thermal imaging applications. The thermal modeling and stress analysis of infrared radiation bolometer which is made of a thin film of aSi:H has been performed using FLUENT(6.1) and ANSYS (11) CFD programs respectively. This bolometer is realized in a multilevel electro thermal structure having a high fill factor. Using the multilevel structure, thermal isolation can be independently optimized without sacrificing the IR absorption area. The analysis showed that optimization of the arm dimensions can be done without failure of structure breakdown or buckling. The design shows that the thermal time constant is 12.95 ms, the responsivity is of 4.65×10³ V/W, and the detcetivity is of 7.97×10⁸ cm Hz^1/2 w^-1 which can be achieved in a 50μm×50μm michromachined structure.