Essential Physics of the OFF-State Current in Nanoscale MOSFETs and Tunnel FETs

Esseni, D.; Pala, Marco G.; Rollo, Tommaso

doi:10.1109/ted.2015.2458171

Cited by 36 publications

(18 citation statements)

References 31 publications

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“…As already mentioned in sections 3 and 4, the design of TFETs is very demanding in terms of electrostatic integrity and requires very small semiconductor film thicknesses (for planar MOSFETs) or small effective diameters (for FinFETs or nanowire MOSFETs) [141,149], which in turn result in significant bandgap widening effects and consequent degradation of the on current [124]. The subthreshold region is furthermore vulnerable to the effects of interface defects, that are among the most serious hurdles to achieve small sub-V T swings [138,144].…”

Section: Tunnel Fets Based On 2d Crystals and Van Der Waals Hetero-stmentioning

confidence: 99%

A review of selected topics in physics based modeling for tunnel field-effect transistors

Esseni

Pala

Palestri

et al. 2017

Semicond. Sci. Technol.

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The research field on tunnel-FETs (TFETs) has been rapidly developing in the last ten years, driven by the quest for a new electronic switch operating at a supply voltage well below 1 V and thus delivering substantial improvements in the energy efficiency of integrated circuits. This paper reviews several aspects related to physics based modeling in TFETs, and shows how the description of these transistors implies a remarkable innovation and poses new challenges compared to conventional MOSFETs. A hierarchy of numerical models exist for TFETs covering a wide range of predictive capabilities and computational complexities. We start by reviewing seminal contributions on direct and indirect band-to-band tunneling (BTBT) modeling in semiconductors, from which most TCAD models have been actually derived. Then we move to the features and limitations of TCAD models themselves and to the discussion of what we define non-self-consistent quantum models, where BTBT is computed with rigorous quantum-mechanical models starting from frozen potential profiles and closed-boundary Schrödinger equation problems. We will then address models that solve the open-boundary Schrödinger equation problem, based either on the non-equilibrium Green's function NEGF or on the quantum-transmitting-boundary formalism, and show how the computational burden of these models may vary in a wide range depending on the Hamiltonian employed in the calculations. A specific section is devoted to TFETs based on 2D crystals and van der Waals hetero-structures. The main goal of this paper is to provide the reader with an introduction to the most important physics based models for TFETs, and with a possible guidance to the wide and rapidly developing literature in this exciting research field.

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Section: Tunnel Fets Based On 2d Crystals and Van Der Waals Hetero-stmentioning

confidence: 99%

A review of selected topics in physics based modeling for tunnel field-effect transistors

Esseni

Pala

Palestri

et al. 2017

Semicond. Sci. Technol.

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“…Please note that we do not account for Source-to-Drain Tunneling (SDT) and band-to-band tunneling (BTBT) that set a lower limit to the minimum attainable OFF-current and may prevent to achieve I off = 100 nA/µm in very short channel devices. However, both experiments [43], [44], [45] and simulations [46] demonstrate that I off = 100 nA/µm is feasible for V DD = 0.6 V or below in InAs and In 0.53 Ga 0.47 As UTB devices. Since, GaAs has a wider bandgap than InAs or In 0.53 Ga 0.47 As, it is reasonable to assume that BTBT does not play a critical role in the device considered in this work.…”

Section: Results: Static Performancementioning

confidence: 99%

Quasi-Ballistic $\Gamma $ - and L-Valleys Transport in Ultrathin Body Strained (111) GaAs nMOSFETs

Caruso

Palestri

Lizzit

et al. 2016

IEEE Trans. Electron Devices

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Abstract-We carefully scrutinize the potential of ultra thin body strained (111) GaAs MOSFETs to achieve better performance than other GaAs-based channel FETs at scaled channel length and with relaxed thickness requirements thanks to Lvalleys enhanced Density of States and carrier transport. Calibrated Multi-Subband Monte Carlo simulations including scattering provide the modeling framework necessary for accurate simulations.The results show that L-valley-enhanced transport most likely will not yield the Ion and switching time improvements observed in simple ballistic simulations, even if considering ideal material properties and purely phonon scattering limited transport. In fact, the increased Density of States and inversion charge at the virtual source provided by the L-valleys in the strained material is counterbalanced by an increased phonon scattering rate and reduced carrier velocity.

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“…In recent experimental demonstration, III‐V TFET has achieved ON current of 92 μA/μm with 48‐mV/dec subthreshold swing at a supply voltage ( V DD ) of 0.5 V. With high ON to OFF current ratio and lower subthreshold swing, TFET digital circuits achieve ultralow power consumption and high energy efficiency . However, TFET shows peculiar electrical characteristics such as ambipolarity and unidirectional current conduction . Ambipolarity in TFETs is considered as a serious challenge, and several device‐level optimization techniques were demonstrated to reduce the ambipolar leakage .…”

Section: Introductionmentioning

confidence: 99%

“…10,11 However, TFET shows peculiar electrical characteristics such as ambipolarity and unidirectional current conduction. 12,13 Ambipolarity in TFETs is considered as a serious challenge, and several device-level optimization techniques were demonstrated to reduce the ambipolar leakage. 14,15 Recently, it has been experimentally reported that TFET exhibits significant p-i-n leakage leading to malfunction in TFET-based circuits without the contribution of ambipolar leakage in TFET devices.…”

Section: Introductionmentioning

confidence: 99%

Tunnel FET‐based ultralow‐power and hardware‐secure circuit design considering p‐i‐n forward leakage

Japa

Majumder

Sahoo

et al. 2020

Circuit Theory & Apps

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Summary Tunnel field‐effect transistor (TFET) exhibits significant p‐i‐n forward leakage with the increase in drain‐to‐source voltage bias, and this adversely impacts the power consumption and reliability of TFET digital circuits. This work presents low‐power circuit techniques that result in novel compact gates and recommends tristate gates to mitigate the leakage effects. The proposed novel compact gates and tristate gates demonstrate two and six times lower power consumption compared with conventional TFET transmission gates with enhanced reliability. Further, this work introduces a new design methodology that leverages TFET p‐i‐n forward leakage for hardware obfuscation applications. Utilizing the proposed design methodology, the optimization of 40% and 80% in area and power consumption of hardware security primitives like true random number generators is also accomplished.

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Essential Physics of the OFF-State Current in Nanoscale MOSFETs and Tunnel FETs

Cited by 36 publications

References 31 publications

A review of selected topics in physics based modeling for tunnel field-effect transistors

A review of selected topics in physics based modeling for tunnel field-effect transistors

Quasi-Ballistic $\Gamma $ - and L-Valleys Transport in Ultrathin Body Strained (111) GaAs nMOSFETs

Tunnel FET‐based ultralow‐power and hardware‐secure circuit design considering p‐i‐n forward leakage

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