The mitigation of signal integrity issues in coupled MWCNT bundles and a comparison with Cu interconnects

Abstract

In the nanoscale regime, carbon nanotubes (CNTs) are being considered as a future alternative interconnect material for traditional copper (Cu) wires in integrated circuit technology. The advances in device scaling and the continuous increase of clock frequencies in very large-scale integration technology have resulted in signal integrity (SI) issues. The reduction of such SI issues in coupled multiwalled CNT bundle interconnects is evaluated herein. The worst-case crosstalk delay and peak noise voltage are simulated for three-line coupled interconnects at the 22-nm technology node. To minimize the crosstalk effects, a passive shielding technique is proposed, resulting in reductions of 15.3% and 40.8% in the dynamic in-phase and out-phase crosstalk condition, respectively. The SI of single- and two-line coupled MWCNT bundle interconnects is also investigated based on eye diagrams in a channel simulator and compared with that of Cu interconnects. The eye-opening height is significantly enhanced in the MWCNT bundle and Cu interconnects when using the proposed technique. Moreover, the MWCNT bundle has a higher eye-opening compared with its Cu counterpart.