Modeling and Performance Analysis of Double Gate Carbon Nanotube Field Effect Transistor

Abstract

Since several years ago, it has been understood that silicon transistors are difficult to further shrink after a particular feature size. In next decade or two, ability to advance MOSFET technology will start to decline, necessitating a rush to find a replacement. The present research investigates the possibility of replacing traditional MOSFETs due to a variety of short-channel effects, including threshold voltage variations, leakage current, and drain-induced barrier lowering at the nanoscale. Researchers are looking at using carbon nanotubes rolled-up graphene sheets instead of silicon in electronic devices. Replacement of MOSFETs with this new kind of transistors, referred to as carbon nanotube field effect transistors (CNTFETs), is currently a leading technology at nanoscale. With their excellent thermal conductivities, high current drivability and superior transport characteristics, use of CNTs have emerged as a potential replacement for bulk CMOS technology. Despite all development and advancement, various challenging issues still need to be resolved. Therefore, in order to proceed in research, this thesis reviews all previously done research and explains the research that will be needed in future to produce large-scale VLSI chips using CNTFETs. Models for design and study of CNTFETs are presented in this thesis. Applications for these transistors in emerging field of nanotechnology are being given important consideration. In this work, double gate carbon nanotube field effect transistor (DG-CNTFET) are considered to overcome various short channel effects. An analytical model that is temperature dependent has been proposed for drain current of DG-CNTFET to analyse device performance at variable temperature range. This developed model is used to obtain current-voltage characteristics of DG-CNTFET in MATLAB to compare results obtained in nano TCAD ViDES. For varying temperature ranges, several performance parameters including output characteristics, ON and OFF currents, subthreshold swing and drain conductan