Research On The Signal Integrity Of Carbon Nanotube Interconnects

Carbon nanotube (CNT) is a kind of one dimensional nano-material made of carbon atoms. CNT has been studied extensively since it was discovered in 1991. It has good mechanical, thermal and electrical properties. The metallic carbon nanotubes have a low resistance, high thermal conductivity along the tube and a large carrying capacity of current density, which is proposed as potential candidates for replacing on-chip copper interconnects in the future.With the development of circuit design and manufacturing technology in ultra large scale integrated circuit, the size of devices is getting smaller, and the device density is increasing. It should be noted that thermal issues are now becoming challenging factors in high-performance integrated circuit design due to the device scaling trends.In this paper, our research is mainly on the signal integrity of carbon nanotube interconnects in different temperature conditions. We propose two modified temperature-dependent equivalent circuit models for single- and double-walled carbon nanotube (SWCNT & DWCNT) interconnects. The temperature effect on crosstalk noise and delay in single CNT and CNT bundle interconnects are investigated, respectively. The crosstalk-induced noise and delay of these novel interconnects are characterized numerically with HSPICE over a large temperature range. The simulation results show that the crosstalk-induced delay increases significantly and the noise increases slightly while the temperature is raised, which indicate that the performance and reliability degrade with an increase in CNT interconnects temperature. In addition, compared to a single carbon nanotube interconnect, the CNT bundle has more excellent performance, and is more likely to become the ideal interconnect materials.