Optimizing the Ratio of Number of Tubes in PCNTFET to NCNTFET for Digital Circuits

Abstract

Carbon nanotube Field Effect Transistors (CNTFET) offer various benefits as compared to other FETs. Many circuits can be constructed using PCNTFETs (P-type CNTFET) and NCNTFETs (N-type CNTFET) similar to the PMOS and NMOS of the CMOS technology. The CNTFETs employ carbon nanotubes in the channel of the device to provide a path for the ballistic conduction of electrons. The different ratios of number of tubes in channel of the PCNTFET to the number of tubes in the channel of NCNTFET lead to different properties of the device. This paper focuses on determining the ratio of number of tubes in PCNTFET to NCNTFET which gives minimum PDP (Power Delay Product) through analyzing a circuit in which an inverter is loaded with eight inverters. Using the results a 4x4 Baugh-Wooley multiplier is constructed and its performance is compared with a multiplier constructed in a different way.