Performance Comparison Between Current-Mode Signaling and Voltage-Mode Signaling for Single-Walled Carbon Nanotube Bundle Interconnects

Abstract

Compared with the traditional copper material, carbon nanotube (CNT) has been identified as one of the most potential materials for interconnects in nanometer regime due to higher performance. However, for CNT interconnects, most of the researches focus on voltage-mode signaling (VMS) scheme, whereas current-mode signaling scheme (CMS) is meagerly investigated. The paper proposes an equivalent circuit model of two-line coupled single-walled CNT bundle interconnects, which is applicable to both CMS and VMS schemes. In addition, the model takes capacitive and inductive crosstalk into consideration. In CMS and VMS interconnects, the performance of victim line in the time domain is studied according to decoupling technique and ABCD parameter matrix approach at local, intermediate and global levels, respectively. The influence of aggressor line on victim line is discussed because of dynamic crosstalk and functional crosstalk. Furthermore, the paper comparatively analyzes the performance advantage between CMS interconnects and VMS interconnects. The results show that CMS interconnects have lower output voltage swing and propagation delay than VMS interconnects in the same condition. In terms of noise, CMS scheme has higher advantage for lesser noise peak, noise width and noise area. Moreover, it is found that the results obtained by ABCD parameter matrix approach have great consistency with Advanced Design System simulation results.