Abstract
Metamaterial electromagnetic wave absorbers, which usually can be fabricated in a low weight thin film structure, have a
near unity absorptivity in a special waveband, and therefore have been widely applied from microwave to optical
waveband. To increase absorptance of CMOS MEMS devices in 2-5 μmm waveband, multi-color infrared metamaterial
absorbers are designed with CSMC 0.5 μmm 2P3M and 0.18 μmm 1P6M CMOS technology in this work. Metal-insulator-metal
(MIM) three-layer MMAs and Insulator-metal-insulator-metal (MIMI) four-layer MMAs are formed by CMOS
metal interconnect layers and inter metal dielectrics layer. To broaden absorption waveband in 2-5μmm range, MMAs with
a combination of different sizes cross bars are designed. The top metal layer is a periodic aluminum square array or cross
bar array with width ranging from submicron to several microns. The absorption peak position and intensity of MMAs
can be tuned by adjusting the top aluminum micro structure array. Post-CMOS process is adopted to fabricate MMAs.
The infrared absorption spectra of MMAs are verified with finite element method simulation, and the effects of top metal
structure sizes, patterns, and films thickness are also simulated and intensively discussed. The simulation results show
that CMOS MEMS MMAs enhance infrared absorption in 2-20 μmm. The MIM broad MMA has an average absorptance
of 0.22 in 2-5 μmm waveband, and 0.76 in 8-14 μm waveband. The CMOS metamaterial absorbers can be inherently
integrated in many kinds of MEMS devices fabricated with CMOS technology, such as uncooled bolometers, infrared
thermal emitters.
