Titanium Nitride based hybrid plasmonic-photonic waveguides for on-chip plasmonic interconnects

Over the past few decades, photonic technologies have emerged as a promising technology for data communications. They offer advantages such as high data bandwidths at comparable or even lower power consumption than electronics. However, photonic integrated circuits suffer from the diffraction limit of light which is a major obstacle in achieving small device footprints and densely packed on-chip interconnects. In recent years, plasmonics has emerged as a possible solution for densely packed on-chip nanophotonic circuitry. The field of plasmonics deals with oscillations of free electrons in a metal coupled to an electromagnetic field. The large wave-vector associated with these oscillations enables light to be localized in volumes much smaller than the diffraction limit. Consequently, there have been many demonstrations of plasmonic interconnects for on-chip communications, using well known metals such as gold and silver. However these materials are not CMOS compatible and hence their use is not technologically feasible. The growing need for plasmonic materials which are robust, cost-effective, and CMOS-compatible has led to the study of alternate plasmonic materials. For the visible and near infrared ranges, transition metal nitrides have been shown to be suitable metals for plasmonic applications These materials have optical properties comparable to that of gold and are CMOS-compatible, hence, they can be easily integrated into a silicon platform for on-chip applications. In this work, we demonstrate titanium nitride based plasmonic interconnects in an all-solid state geometry which can be easily integrated on a silicon platform.