Doping, Tunnel Barriers, and Cold Carriers in InAs and InSb Nanowire Tunnel Transistors

Sylvia, Somaia Sarwat; Khayer, M. Abul; Alam, Khairul; Lake, Roger K.

doi:10.1109/ted.2012.2212442

Cited by 17 publications

(11 citation statements)

References 31 publications

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“…The reason for such difference in transfer characteristics lies in the fact that, in longer channel length devices ( L CH ≥ 10 nm) the transport is dominated by “cold carrier injection” whereas in shorter length devices, it is controlled by “voltage controlled tunneling” 59 . As pointed out in 59 and also what we find in Fig. 4(a), (b) is that, “voltage controlled tunneling” does not have significant effect on the lowering of SS below the Boltzmann limit and does not vary considerably with gate voltage.…”

Section: Resultsmentioning

confidence: 99%

“…The crossing over of the band edges is resposible for the “low-pass filtering” of the high energy tails of the Fermi distribution function 60 of the source side. As a result, in the low V G regime, transport in long channel TFET is determined by the “cold carrier injection” 59 which entails the 59 , 60 , where Δ ϕ = E v,S − E c,CH . From our calculations it is found that, Δ ϕ ≈ 0.01 eV in HSE TFET and 0.001 eV in PBE TFET.…”

Section: Resultsmentioning

confidence: 99%

“…As V G increases i . e. in the post-subthreshold regime, value of Δ ϕ increases and the transport mechanism shifts to “voltage controlled tunneling” 59 . The SS in both HSE and PBE does not change significantly with gate voltage in this high V G regime (see Fig.…”

Section: Resultsmentioning

confidence: 99%

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Scalability assessment of Group-IV mono-chalcogenide based tunnel FET

Brahma

Kabiraj

Saha

et al. 2018

Sci Rep

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Selection of appropriate channel material is the key to design high performance tunnel field effect transistor (TFET), which promises to outperform the conventional metal oxide semiconductor field effect transistor (MOSFET) in ultra-low energy switching applications. Recently discovered atomically thin GeSe, a group IV mono-chalcogenide, can be a potential candidate owing to its direct electronic band gap and low carrier effective mass. In this work we employ ballistic quantum transport model to assess the intrinsic performance limit of monolayer GeSe-TFET. We first study the electronic band structure by regular and hybrid density functional theory and develop two band k · p hamiltonian for the material. We find that the complex band wraps itself within the conduction band and valence band edges and thus signifies efficient band to band tunneling mechanism. We then use the k · p hamiltonian to calculate self-consistent solution of the transport equations within the non-equilibrium Green’s function formalism and the Poisson’s equation based electrostatic potential. Keeping the OFF-current fixed at 10 pA/μm we investigate different static and dynamic performance metrics (ON current, energy and delay) under three different constant-field scaling rules: 40, 30 and 20 nm/V. Our study shows that monolayer GeSe-TFET is scalable till 8 nm while preserving ON/OFF current ratio higher than 104.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Scalability assessment of Group-IV mono-chalcogenide based tunnel FET

Brahma

Kabiraj

Saha

et al. 2018

Sci Rep

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“…Then, the occurrence of tails becomes questionable and only an atomistic approach, like tight-binding NEGF, is able to correctly simulate the effect. 12,13 ACKNOWLEDGMENTS This work was supported by the European Communitys Seventh Frame-work Programme under Grant 619509 through Project E2SWITCH.…”

Section: Discussionmentioning

confidence: 99%

The effect of density-of-state tails on band-to-band tunneling: Theory and application to tunnel field effect transistors

Sant

Schenk

2017

Journal of Applied Physics

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It is demonstrated how band tail states in the semiconductor influence the performance of a Tunnel Field Effect Transistor (TFET). As a consequence of the smoothened density of states (DOS) around the band edges, the energetic overlap of conduction and valence band states occurs gradually at the onset of band-to-band tunneling (BTBT), thus degrading the sub-threshold swing (SS) of the TFET. The effect of the band tail states on the current-voltage characteristics is modelled quantum-mechanically based on the idea of zero-phonon trap-assisted tunneling between band and tail states. The latter are assumed to arise from a 3-dimensional pseudo-delta potential proposed by Vinogradov [1]. This model potential allows the derivation of analytical expressions for the generation rate covering the whole range from very strong to very weak localization of the tail states. Comparison with direct BTBT in the one-band effective mass approximation reveals the essential features of tail-to-band tunneling. Furthermore, an analytical solution for the problem of tunneling from continuum states of the disturbed DOS to states in the opposite band is found, and the differences to direct BTBT are worked out. Based on the analytical expressions, a semiclassical model is implemented in a commercial device simulator which involves numerical integration along the tunnel paths. The impact of the tail states on the device performance is analyzed for a nanowire Gate-All-Around TFET. The simulations show that tail states notably impact the transfer characteristics of a TFET. It is found that exponentially decaying band tails result in a stronger degradation of the SS than tail states with a Gaussian decay of their density. The developed model allows more realistic simulations of TFETs including their non-idealities.

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“…Si [29] Si [26] s-Si [31] 16 nm FinFET [10] Si, Ghandi (NUS) 16 Figure 6: Simulated TFET subthreshold swing versus drain current per micron from [8]. The TFETs simulations are from Agarwal [16], Avci [17,18], Sylvia [19], Lu [20], Pillai [21], Koswatta [22], Zhang [23,24], Li [25], with FinFET data from Wu [13]. Simulations in [8] show the potential of the TFET relative to CMOS, however significantly more study is needed to understand the effects of band tails [26] due to phonons and heavy-doping, defect-assisted tunneling [27,28], and interface and border traps.…”

Section: State Of the Artmentioning

confidence: 99%

Tunnel field-effect transistors - update

Seabaugh

2014

2014 12th IEEE International Conference on Solid-State and Integrated Circuit Technology (ICSICT)

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Progress in the development of tunnel field-effect transistors (TFETs) is updated. Selected experimental demonstrations and simulations of sub-60-mV/decade TFETs are compared. A universal SPICE model is discussed which allows the unique attributes of the TFET to be represented across material systems and gate geometries to enable circuit design, with the intent of better informing the device development.

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Doping, Tunnel Barriers, and Cold Carriers in InAs and InSb Nanowire Tunnel Transistors

Cited by 17 publications

References 31 publications

Scalability assessment of Group-IV mono-chalcogenide based tunnel FET

Scalability assessment of Group-IV mono-chalcogenide based tunnel FET

The effect of density-of-state tails on band-to-band tunneling: Theory and application to tunnel field effect transistors

Tunnel field-effect transistors - update

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