Tensile strained Ge tunnel field-effect transistors: k · p material modeling and numerical device simulation

Kao, Kuo-Hsing; Verhulst, Anne S.; Put, Maarten L. Van de; Vandenberghe, William G.; Sorée, Bart; Magnus, Wim; Meyer, K. De

doi:10.1063/1.4862806

Cited by 35 publications

(22 citation statements)

References 38 publications

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“…The effect of strain in Ge TFETs has been analyzed in [113] by using quantum-corrected TCAD simulations to estimate the current and · k p calculations for the band parameters. It was found that tensile strain significantly enhances the BTBT rate, similarly to the results for strained Si discussed in section 3.2.…”

Section: Ge-based Tfetsmentioning

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: Ge-based Tfetsmentioning

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.

View full text Add to dashboard Cite

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“…35,36 In relaxed GeSn pTFET, tunneling from the second valence band V2 to Γ conduction band is the dominant component in Fig. 10, it can be seen that G BTBT in tensile strained GeSn pTFET exhibits a higher value than that in relaxed device, which is mainly due to the reduction of direct E G induced by the uniaxial tensile strain.…”

Section: B Gesn Ptfets: Impact Of Uniaxial Tensile Strainmentioning

confidence: 88%

Relaxed germanium-tin P-channel tunneling field-effect transistors fabricated on Si: impacts of Sn composition and uniaxial tensile strain

Han¹,

Wang²,

Liu³

et al. 2015

AIP Advances

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In this work, relaxed GeSn p-channel tunneling field-effect transistors (pTFETs) with various Sn compositions are fabricated on Si. Enhancement of on-state current ION with the increase of Sn composition is observed in transistors, due to the reduction of direct bandgap EG. Ge0.93Sn0.07 and Ge0.95Sn0.05 pTFETs achieve 110% and 75% enhancement in ION, respectively, compared to Ge0.97Sn0.03 devices, at VGS - VTH = VDS = - 1.0 V. For the first time, ION enhancement in GeSn pTFET utilizing uniaxial tensile strain is reported. By applying 0.14% uniaxial tensile strain along [110] channel direction, Ge0.95Sn0.05 pTFETs achieve 12% ION improvement, over unstrained control devices at VGS - VTH = VDS = - 1.0 V. Theoretical study demonstrates that uniaxial tensile strain leads to the reduction of direct EG and affects the reduced tunneling mass, which bring the GBTBT rising, benefiting the tunneling current enhancement in GeSn TFETs.

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“…9 Enhancing the BTBT rate of direct gap Ge 1−x Sn x alloys is important for high-performance TFETs in application. The direct gap BTBT generation rate G can be described by Kane's model in the form 33,34 …”

Section: Resultsmentioning

confidence: 99%

Effects of uniaxial strain on electron effective mass and tunneling capability of direct gap Ge1−xSnx alloys

et al. 2016

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Direct gap Ge1−xSnx alloys under [100] and [110] uniaxial strain are comprehensively investigated by theoretical calculations using the nonlocal empirical pseudopotential method (EPM). It is shown that [100] uniaxial tensile strain aids indirect-to-direct gap transition in Ge1−xSnx alloys. The Γ electron effective mass along the optimal direction under [110] uniaxial strain is smaller than those under [100] uniaxial strain and (001) biaxial strain. Additionally, the direct tunneling gap is smallest along the strain-perpendicular direction under [110] uniaxial tensile strain, resulting in a maximum direct band-to-band tunneling generation rate. An optimal [110] uniaxial tensile strain is favorable for high-performance direct gap Ge1−xSnx electronic devices.

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Tensile strained Ge tunnel field-effect transistors: k · p material modeling and numerical device simulation

Cited by 35 publications

References 38 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

Relaxed germanium-tin P-channel tunneling field-effect transistors fabricated on Si: impacts of Sn composition and uniaxial tensile strain

Effects of uniaxial strain on electron effective mass and tunneling capability of direct gap Ge1−xSnx alloys

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