On the Static and Dynamic Behavior of the Germanium Electron-Hole Bilayer Tunnel FET

Lattanzio, Livio; Daǧtekın, Nilay; Michielis, L. De; Ionescu, Adrian M.

doi:10.1109/ted.2012.2211600

Cited by 35 publications

(16 citation statements)

References 26 publications

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“…In the presence of quantization, different modeling approaches can be followed depending on the different alignment between tunneling and quantization directions. In fact, in a planar device, tunneling can be in-line with the quantization direction, as in the EHBTFET [28], or it can be transverse to the quantization direction. In this paragraph we give more details for the case with tunneling aligned with quantization because the picture changes more dramatically compared to the transverse quantization case, for which expressions similar to equation (11) have been proposed, where only the prefactor is different due to the different dimensionality ofk [29,30].…”

Section: Models For Direct Btbt In Bulk Semiconductorsmentioning

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: Models For Direct Btbt In Bulk Semiconductorsmentioning

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

show abstract

“…Similarly, for the DG TFET, the probability of the maximum V turn-on is 7.8 × 10 −2 % (0.6 14 ) and the probability of the minimum V turn-on is 2.7 × 10 −4 % (0.4 14 ). In the case of the EHBTFET, as tunneling occurs from the valence band of the channel near SG to the conduction band of the channel near MG, the V turn-on reaches the maximum when all MG grains have a WF of 4.6 eV and all SG grains have a WF of 4.4 eV where MG and SG overlap, as shown in Figure 5a; its probability is 2.0 × 10 −20 % (0.6 35 × 0.4 35 ). Additionally, in the opposite case, as shown in Figure 5b, the V turn-on reaches the minimum and its probability is equal to the probability of the maximum V turn-on .…”

Section: Resultsmentioning

confidence: 99%

“…In the case of the planar TFET and DG TFET, a tunneling current occurs along the channel (lateral tunneling) at the source junction. On the contrary, the tunneling current of the EHBTFET is generated across the channel (vertical tunneling) at the body between two gates, and the electrical characteristics of this structure have been actively studied through TCAD simulations and modeling [34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Work-Function Variation Effects in a Tunnel Field-Effect Transistor Depending on the Device Structure

Kım

Kim

et al. 2020

Applied Sciences

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Metal gate technology is one of the most important methods used to increase the low on-current of tunnel field-effect transistors (TFETs). However, metal gates have different work-functions for each grain during the deposition process, resulting in work-function variation (WFV) effects, which means that the electrical characteristics vary from device to device. The WFV of a planar TFET, double-gate (DG) TFET, and electron-hole bilayer TFET (EHBTFET) were examined by technology computer-aided design (TCAD) simulations to analyze the influences of device structure and to find strategies for suppressing the WFV effects in TFET. Comparing the WFV effects through the turn-on voltage (Vturn-on) distribution, the planar TFET showed the largest standard deviation (σVturn-on) of 20.1 mV, and it was reduced by −26.4% for the DG TFET and −80.1% for the EHBTFET. Based on the analyses regarding metal grain distribution and energy band diagrams, the WFV of TFETs was determined by the number of metal grains involved in the tunneling current. Therefore, the EHBTFET, which can determine the tunneling current by all of the metal grains where the main gate and the sub gate overlap, is considered to be a promising structure that can reduce the WFV effect of TFETs.

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“…The only architectural difference between a conventional density gradient (DG)-TFET and the EHBTFET is the asymmetric placement and biasing of the gates. This is required to create gate-source (-drain) underlaps to prevent lateral tunneling [10].…”

Section: Device Working Principlementioning

confidence: 99%

Quantum Mechanical Study of the Germanium Electron–Hole Bilayer Tunnel FET

Alper

Lattanzio

Michielis

et al. 2013

IEEE Trans. Electron Devices

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The electron-hole bilayer tunnel field-effect transistor (EHBTFET) is an electronic switch that uses 2-D-2-D sub-band-to-sub-band tunneling (BTBT) between electron and hole inversion layers and shows significant subthermal swing over several decades of current due to the step-like 2-D density of states behavior. In this paper, EHBTFET has been simulated using a quantum mechanical model. The model results are compared against transactions on computer-aided design simulations and remarkable differences show the importance of quantum effects and dimensionality in this device. Ge EHBTFET with channel thickness of 10 nm results as a promising device for low supply voltage, subthreshold logic applications, with a super steep switching behavior featuring SS avg ∼ 40 mV/dec up to V DD . Furthermore, it has been demonstrated that high ON current levels (∼40 µA/µm) can be achieved due to the transition from phonon-assisted BTBT to direct BTBT at higher biases.Index Terms-2-D-2-D tunneling, band-to-band tunneling (BTBT), density of states (DOS), electron-hole bilayer tunnel field-effect transistor (EHBTFET), germanium, quantum mechanical (QM) simulation, subthreshold slope, tunnel field-effect transistor (TFET).

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On the Static and Dynamic Behavior of the Germanium Electron-Hole Bilayer Tunnel FET

Cited by 35 publications

References 26 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

Analysis of Work-Function Variation Effects in a Tunnel Field-Effect Transistor Depending on the Device Structure

Quantum Mechanical Study of the Germanium Electron–Hole Bilayer Tunnel FET

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