Study on Performance of Si₃N₄ Enhanced Microbolometer with Salicided Polysilicon Thermistor in CMOS Technology

In this paper, we studied the enhancement of additional Si3N4 layer on the voltage responsivity and detectivity of Si-based microbolometer in the standard CMOS process, which is composed of a SiO 2 absorber coupled with a salicided poly-Si thermistor The FDTD simulation results show that the growth of Si3N4 can improve the absorptivity of the microbolometer at $7-13\mu\mathrm{m}$ wavelength and optimal thickness is 500 nm. The experimental results show that the responsivity and detectivity can be improved after deposition of Si3N4 significantly. Especially, the enhancement of the detectivity can reach the maximum of 122% and 29.6% at $11.5\ \mu \mathrm{m}$ and $8.5\mu \mathrm{m}$ , respectively.