CMOS MEMS infrared source based on black silicon

Abstract

In this work, a MEMS infrared source applied to compact Non-Dispersive Infrared (NDIR) gas sensor is reported. Compared to other related things, the source coats integrated nanostructure black silicon compatible with CMOS technique on the poly-silicon. Hence the emissivity is as high as 98% at 3~5μm wave range; relatively the radiation efficiency is increased by 40% through calculation. Suspension structure and DRIE release process of the back side are used in the design to reduce the heat conduction losses, and the source is only sized 3×3mm2 suitable for mass production. After being packed, the source can rapidly heat in 20 ms, besides the modulation depth can reach 30% below 50Hz, which all meet the requirements of the NDIR gas sensor.