Plasmonic interconnects for global wires in integrated circuits

Surface plasmon polaritons (SPPs) are bound electromagnetic waves propagating at a dielectric-metal interface, which have gained attention for high performance and ability for miniaturisation in high-speed dense circuits, due to their subwavelength properties. A dielectric-metal-dielectric (I-M-I) plasmonic waveguide with a 40 nm thick metal or metal-like strip on silicon substrate is proposed for intra-chip communication. The propagation characteristics of the I-M-I waveguide are investigated by numerical simulation and the modes are experimentally verified by scanning near-field optical microscopy. Metal lines as thin as 40 nm can have propagation lengths as large as 239 μm, which has small footprint compatible with the advanced interconnect process.