CMOS Compatible Fabrication of Mid Infrared Microspectrometers Based on an Array of Metamaterial Absorbers

Abstract

The design of a mid-infrared micro-spectrometer based on an array of differently tuned narrow-band metamaterial absorbers is presented. The spectral response is tailored by the design of the unit cell. Each spectral band is composed of a thermopile detector with a 300 ×180 μm² Al-based metamaterial absorber fabricated in a CMOS compatible post-process. The challenges in the fabrication of the sub-μm features within the unit cell over a several mm² absorber area by equipment that is part of the standard infrastructure of a MEMS facility is addressed. The design and fabrication method utilized here for the first time enables the CMOS fabrication of integrated large-area plasmonic components on thermal detectors.