Novel CMOS-Compatible Mo-AlN-Mo Platform for Metamaterial-Based Mid-IR Absorber

Abstract

We demonstrate a new CMOS compatible metal-dielectric-metal (Mo-AlN-Mo) platform of metamaterial absorber for refractory and narrowband applications at mid-IR. Comparison with the recently reported CMOS compatible plasmonic TiN shows superior reflectivity of Mo thin film at mid-IR wavelengths (3-8 μm), while AlN provides large thermal stability and thermal conductivity, mid- to far-IR transparency and both second and third order nonlinear effect and satisfies the matching condition of thermal expansion coefficient with Mo toward minimizing the thermal stress. We demonstrate the proof-of-concept of reducing the thermal stress up to 400° by considering a high stress, CMOS platform of SiO . We further report temporal measurement of the resonance intensity and wavelength-shift of the absorber structures and confirm the robust performance of the platform over prolonged heating. Finally, we propose a method to perform surface enhanced infrared absorption (SEIRA) spectroscopy of biological samples demanding biocompatibility on the massively scalable CMOS platform and demonstrate strong coupling to the amide vibrational bonds of silk fibroin at mid-IR. We envisage the proposed platform will be a versatile avenue for thermophotovoltaic energy conversion and emission at low thermal stress, fast thermal detection, and large scale, low form factor, and integrated sensors with the ubiquitous CMOS technology. 2