Interconnect Design for Subthreshold Circuits

Designing ultralow-power (ULP) efficient very large scale integration digital circuits have received widespread attention due to the rapid growth of portable applications. Device operating in subthreshold region has a strong potential toward satisfying the ULP conditions of portable systems. This paper mainly investigated and compared the performance of single-wall carbon nanotube (SWCNT), Cu, and mixed CNT bundle interconnects for different interconnect lengths and biasing levels under subthreshold conditions. It proposes that individual SWCNT can be used for short and intermediate length interconnects at different bias points in the subthreshold region due to less critical interconnect resistance contrary to superthreshold region. Furthermore, performance analysis of global interconnect shows that in moderate subthreshold region, scaled Cu interconnect performs better than individual SWCNT and mixed CNT bundle, whereas in deep subthreshold region individual SWCNT is still better.