Numerically Efficient Modeling of CNT Transistors With Ballistic and Nonballistic Effects for Circuit Simulation

Abstract

Abstract-This paper presents an efficient carbon nanotube (CNT) transistor modeling technique which is based on cubic spline approximation of the non-equilibrium mobile charge density. The approximation facilitates the solution of the selfconsistent voltage equation in a carbon nanotube so that calculation of the CNT drain-source current is accelerated by at least two orders of magnitude. A salient feature of the proposed technique is its ability to incorporate both ballistic and nonballistic transport effects without a significant computational cost. The proposed models have been extensively validated against reported CNT ballistic and non-ballistic transport theories and experimental results.Index Terms-Carbon nanotube transistors, numerical modeling, non-ballistic effects, circuit simulation.

Quantum analytical modeling and simulation of CNT on insulator (COI) and CNT on nothing (CON) FET: a comparative analysis

“…Again, E vh1 and E vh2 being Van Hove Singularity [9][10][11][12][13][14][15][16][17][18]24] energies where DOS is real and finite to be:…”

“…Having strong carbon-carbon bond in the planar honeycomb structure of graphite [9], the modulus of elasticity at its basal plane is superior than most of the materials known has proved itself trustworthy as per their fabrication is concerned. Near ballistic transport [14,15] of mobile carriers through the CNT channel can be observed with the absence of dangling bonds. In this paper, keeping channel length 20 nm and taking diameter of nanotube 1.5 nm for optimum transport, we have analytically modeled COI/CON devices [19] influenced with quantum mechanical [16,[20][21][22][23] effects as dimensions can be compared with the De-Broglie wavelength.…”

“…From the very invention in 1991 by S. Iijima [9], CNT being a rolled graphite sheet in tubular form [10][11][12][13][14][15][16] originating Quasi-1 dimensional approach [17,18] in nano-science has been considered attractive by scientists to be used in non-classical devices as it holds exceptional mechanical and electrical properties [9,18] like very high tensile strength, high flexibility and elasticity, low thermal expansion coefficient, high electrical conductivity and can be found with significantly high aspect ratio. Conductivity of CNT sincerely depends upon its chirality [17,18], diameter of nanotube and degree of twist [10].…”

Impacts of Parameter Scaling for Low-Power Applications Using CNTFET (Carbon Nanotube Field Effect Transistor) Models: A Comparative Assessment

“…This model is based on cubic spline approximation of non-equilibrium mobile charge density, where approximations were made to solve for the self-consistent voltage originally defined as a non-linear function of terminal capacitance reducing the cost of the number of Newton-Raphson iterations needed [14]. Consequently, the model was developed to get around the main stumbling block in circuit-compatible modeling for CNTFETs, supplemented by the fact that accurate calculations for mobile charges inherently involve numerical integration of the DOS (density of states) given by Eqs.…”

“…In recent years, ongoing research endeavors have revealed a number of CNTFET computer models that are compatible with SPICE that helps a great deal in evaluating delays, estimating power requirements and simulating any performance degradation. Further, it makes multiple transistor circuit simulations more viable [10][11][12][13][14][15].…”