Optical Property Analysis of Microbolometer Based on MEMS

The optical constant of TiN and amorphous silicon thin film as well as film thickness of thermal resistive amorphous silicon were measured by ellipsometry apparatus, which were in agreement with the result from SEM section analysis. According to optical admittance matrix theory, relation between sensing film thickness, resonant cavity height of microbolometer and infrared absorptivity was simulated using FEA (Finite Element Analysis) MatLab software. Optimal film thickness and resonant cavity height for high infrared absorptivity ranging from 3–5 to 8–14 μm atmosphere window infrared bands were achieved, which provides reliable evidence to improve the sensitivity of microbolometer.