Improvement in Electrical Properties of Carbon Nanotube Via Interconnects

We report on the electrical properties of carbon nanotube (CNT) via interconnects with improvement in contact formations between the CNT via and metal electrodes. For the improvement of the bottom contact formation, a TiN/TaN multilayer on a Cu bottom wiring layer is applied to suppress formation of a highly resistive oxide layer on the TaN barrier layer. The top electrode formation with good coverage on CNTs reduces contact resistance. The current–voltage characteristics of ultrafine CNT via interconnects exhibit ohmic behavior. The resistance of the CNT via interconnect is inversely proportional to the via area, indicating that the CNT bundles are grown with uniform quality and density in various-diameter via holes.