Plasmonic germanium resonators for CMOS compatible Terahertz chem-bio sensing platform

Plasmon resonance based biosensors are considered as one of the most sensitive bio detection methods, in which the sensitivity is of the order of a single biomolecule due to extremely high enhancement of the electromagnetic field. Although established metal plasmonic biosensors are extremely sensitive, they suffer from integration issues due to non-compatibility to standard semiconductor fabrication technology (CMOS technology) [1]. Additionally, metal plasmonic sensors operate in the Near IR to visible spectral range, therefore, essentially leaving a gap in the Terahertz (THz) spectral regime which is interesting for biological applications like detection of conformational changes in proteins. On the other hand, doped semiconductor materials show plasmonic behaviour in the THz spectral regime [1, 2], and can be integrated on standard semiconductor foundry processes. This work demonstrates plasmon based Germanium (Ge) resonators fabricated on standard BiCMOS technology operating at THz frequency range for chem-bio sensing.