Performance analysis of CNFET based circuits in the presence of fabrication imperfections

This paper presents a comprehensive analysis of the impact of CNT fabrication imperfections on the performance of multichannel Carbon Nanotube FET (CNFET) -based devices. In particular, we introduce a methodology for stochastically estimating the impact of spacing between adjacent tubes and the impact of its variation. This enables accurate prediction of the reduction in drive current due to the removal of tubes, the increase in spacing between adjacent tubes, and variations in tube diameter and spacing. In multichannel CNFETs, when the number of channels (CNTs) is greater than eight, our experiments show that variations in tube diameter and inter-tube spacing result in less than 8% performance variation. Monte Carlo simulation results, however, show that the removal of tubes increases variation in ION from 13% to 26% due to larger variation in inter-tube spacing. The presented realistic analysis and the proposed methodology can be extremely useful in variation-tolerant CNFET-based circuit design.