Gate capacitance modeling and width-dependent performance of graphene nanoribbon transistors

Kliros, George S.

doi:10.1016/j.mee.2013.04.011

Cited by 36 publications

(27 citation statements)

References 25 publications

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“…Steady-state quantum simulations based on the NEGF (nonequilibrium Green's function) approach assuming ballistic transport have been performed [21][22][23][24][25] and GNR MOSFET simulations taking edge scattering [26,27] and phonon scattering [25] into account have been conducted. Moreover, the RF performance of GNR MOSFETs has been investigated by numerical simulations [21,22,25] and analytical equations have been developed to calculate the steady-state behavior and the RF properties of GNR MOSFETs [28].…”

Section: Introductionmentioning

confidence: 99%

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Simulation of 50-nm Gate Graphene Nanoribbon Transistors

et al. 2016

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An approach to simulate the steady-state and small-signal behavior of GNR MOSFETs (graphene nanoribbon metal-semiconductor-oxide field-effect transistor) is presented. GNR material parameters and a method to account for the density of states of one-dimensional systems like GNRs are implemented in a commercial device simulator. This modified tool is used to calculate the current-voltage characteristics as well the cutoff frequency f T and the maximum frequency of oscillation f max of GNR MOSFETs. Exemplarily, we consider 50-nm gate GNR MOSFETs with N = 7 armchair GNR channels and examine two transistor configurations. The first configuration is a simplified MOSFET structure with a single GNR channel as usually studied by other groups. Furthermore, and for the first time in the literature, we study in detail a transistor structure with multiple parallel GNR channels and interribbon gates. It is shown that the calculated f T of GNR MOSFETs is significantly lower than that of GFETs (FET with gapless large-area graphene channel) with comparable gate length due to the mobility degradation in GNRs. On the other hand, GNR MOSFETs show much higher f max compared to experimental GFETs due the semiconducting nature of the GNR channels and the resulting better saturation of the drain current. Finally, it is shown that the gate control in FETs with multiple parallel GNR channels is improved while the cutoff frequency is degraded compared to single-channel GNR MOSFETs due to parasitic capacitances of the interribbon gates.

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Section: Introductionmentioning

confidence: 99%

“…This has led to overly optimistic performance predictions such as unrealistically high simulated cutoff frequencies [21,22,25,28]. Moreover, most simulations have been performed using in-house tools not accessible by the community.…”

Section: Introductionmentioning

confidence: 99%

Simulation of 50-nm Gate Graphene Nanoribbon Transistors

et al. 2016

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“…In 2011, Sako et al [13] investigated the effects of edge bond relaxation in device performance using top-of-the barrier model for the 10 nm gate length by incorporating the effective mass of first subband. More recently, in 2013, Kliros [16] studied the effect of width-dependent performance of GNR FETs using an analytical model. However, performance studies of armchair GNR families with channel length below 10 nm is to be researched, and a more comprehensive investigation is thus warranted based on more sophisticated approaches.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, the method is inaccurate for investigating the role of GNR width as a key attribute in static performance of GNR FETs. In addition, the existence of mismatch between the parabolic band approximation and the exact dispersion relation in analytical models [16], top-of-the-barrier model [26] or semi-analytical model [27] can have an erroneous estimation of actual concentration of carriers in the channel. The accurate results and deeper physical insight can be achieved by atomistic quantum transport models at the expense of long computational times.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the width-dependent static characteristics of graphene nanoribbon field effect transistors using non-parabolic quantum-based model

Banadaki

Srivastava

2015

Solid-State Electronics

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“…By scaling the channel, however, the drain and source voltages can change the potential and the corresponding charges in the channel, especially when the quantum capacitance is increased at ON-state, thereby urging the numerical simulation for accurate investigation of the device performance [18]. In addition to change in the insulator capacitance by GNR width, the density of state of GNR and the corresponding quantum capacitance as a function of gate voltage can be also altered by scaling the GNR width [19]. Furthermore, band-to-band tunneling (BTBT) from drain to channel can be significantly changed by scaling the GNR width corresponding to the size of the induced bandgap along with the increase in direct source-to-drain tunneling by scaling the channel length.…”

Section: Introductionmentioning

confidence: 99%

Scaling Effects on Static Metrics and Switching Attributes of Graphene Nanoribbon FET for Emerging Technology

Banadaki

Srivastava

2015

IEEE Trans. Emerg. Topics Comput.

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In this paper, we have investigated the static metrics and switching attributes of graphene nanoribbon field effect transistors (GNR FETs) for scaling the channel length from 15 nm down to 2.5 nm and GNR width by approaching the ultimate vertical scaling of oxide thickness. We have simulated the double gate GNR FET by solving a numerical quantum transport model based on self-consistent solution of the 3D Poisson equation and 1D Schrödinger equation within the non-equilibrium Green's function formulism. The narrow armchair GNR, e.g. (7,0), improved the device robustness to short channel effects, leading to better OFF-state performance considering OFF-current, ION/IOFF ratio, subthreshold swing and drain-induced barrierlowering. The wider armchair GNRs allow the scaling of channel length and supply voltage resulting better ON-state performance such as the larger intrinsic cut-off frequency for the channel length below 7.5 nm at smaller gate voltage as well as smaller intrinsic gate-delay time with the constant slope for scaling the channel length and supply voltage. The wider armchair GNRs, e.g. (13,0), have smaller power-delay product for scaling the channel length and supply voltage, reaching to ~0.18(fJ/µm).

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Gate capacitance modeling and width-dependent performance of graphene nanoribbon transistors

Cited by 36 publications

References 25 publications

Simulation of 50-nm Gate Graphene Nanoribbon Transistors

Simulation of 50-nm Gate Graphene Nanoribbon Transistors

Investigation of the width-dependent static characteristics of graphene nanoribbon field effect transistors using non-parabolic quantum-based model

Scaling Effects on Static Metrics and Switching Attributes of Graphene Nanoribbon FET for Emerging Technology

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