Impact of Asymmetric Configurations on the Heterogate Germanium Electron&amp;#x2013;Hole Bilayer Tunnel FET Including Quantum Confinement

IEEE Trans. Electron Devices

et al. 2016

An extensive parameter analysis is performed on the Electron-Hole Bilayer Tunnel FET (EHBTFET) using a 1D effective mass (EMA-NP) Schrödinger/Poisson solver with non-parabolic corrections considering thin InAs, In0.53Ga0.47As, Ge, Si0.5Ge0.5 and Si films. It is found that depending on the channel material and channel thickness, the EHBTFET can operate either as a 2D-2D or 3D-3D tunneling device. InAs offers the highest ION, whereas for Si and Si0.5Ge0.5 EHBTFET significant current levels cannot be achieved within a reasonable voltage range. The general trends are explained through an analytical model which shows a close agreement with numerical results.

Section: Performance Considerations and Impact Of Channel Materialsmentioning

confidence: 70%

The Electron-Hole Bilayer TFET: Dimensionality Effects and Optimization

Alper

Palestri

IEEE Trans. Electron Devices

et al. 2016

“…The TCAD simulation scheme that we follow using Synopsys [19] is similar to that previously discussed and tested in recent works [7], [22]. However, the nature of the device herein analyzed allowed us to modify it in order to speed up the simulations execution.…”

Section: Tcad Simulation Approachmentioning

confidence: 99%

“…The first one is a Multi-Subband Ensemble Monte Carlo (MS-EMC) simulator specifically designed for this aim. The second (used for comparison purposes) is a customized TCAD-based approach including quantum effects that has extensively been used in the last years [7], [8]. Furthermore, for the MS-EMC, we assess the impact on the BTBT generation rate distribution of two different tunneling path choices.…”

Section: Introductionmentioning

confidence: 99%

Implementation of Band-to-Band Tunneling Phenomena in a Multisubband Ensemble Monte Carlo Simulator: Application to Silicon TFETs

Medina-Bailón

IEEE Trans. Electron Devices

Sampedro

et al. 2017

TFETs are in the way to become an alternative to conventional MOSFETs due to the possibility of achieving low subthreshold swing (SS) combined with small OFF current levels which allows operation at low VDD. In this work, a non-local band-to-band tunneling (BTBT) model has been successfully implemented into a Multi-Subband Ensemble Monte Carlo (MS-EMC) simulator and applied to ultra-scaled silicon-based n-type TFETs. We have considered two different criteria for the choice of the tunneling path followed by the carriers when crossing the potential barrier, which leads to different distributions of the generated electron-hole pairs. Subband discretization due to field-induced quantum confinement has been taken into account. TCAD simulations accounting for quantization effects are considered for comparison purposes providing very accurate agreement with MS-EMC results.Index Terms-tunnel field-effect transistors, TFET, quantum confinement, band-to-band tunneling, BTBT, Multi-Subband Ensemble Monte Carlo, MS-EMC.

“…5 Moreover, the consideration of quantum confinement effects showed the appearance of parasitic diagonal leakage tunneling between regions with different degrees of quantization. 6 To overcome this parasitic leakage, a heterogate EHBTFET (HG-EHBTFET) was proposed, 6 along with a solution to alleviate the large electric fields through the utilization of asymmetric configurations 7 and pseudo-bilayer structures. 8 Notwithstanding the foregoing solutions that showed improved performance, there was still the issue of low ON current levels reported from indirect materials like germanium.…”

mentioning

confidence: 99%

“…The simulation approach followed in this work differs from that reported in others [6][7][8] where a two-step setup integrating the TCAD simulator Silvaco ATLAS (v.5.20.2.R) 17 and Synopsys Sentaurus (v.2014.09) 18 treated BTBT as a postprocessing phenomenon. That approach worked well as long as the total injected charge via BTBT turned out to be negligible compared to the total charge distribution obtained in the absence of tunneling by solving in a self-consistent way the Schr€ odinger and Poisson equations employing the effective mass approximation.…”

mentioning

confidence: 99%

Confinement-induced InAs/GaSb heterojunction electron–hole bilayer tunneling field-effect transistor

Applied Physics Letters

Medina-Bailón

Alper

et al. 2018

Self Cite

Electron-Hole Bilayer Tunneling Field-Effect Transistors are typically based on band-to-band tunneling processes between two layers of opposite charge carriers where tunneling directions and gate-induced electric fields are mostly aligned (so-called line tunneling). However, the presence of intense electric fields associated with the band bending required to trigger interband tunneling, along with strong confinement effects, has made these types of devices to be regarded as theoretically appealing but technologically impracticable. In this work, we propose an InAs/GaSb heterostructure configuration that, although challenging in terms of process flow design and fabrication, could be envisaged for alleviating the electric fields inside the channel, whereas, at the same time, making quantum confinement become the mechanism that closes the broken gap allowing the device to switch between OFF and ON states. The utilization of induced doping prevents the harmful effect of band tails on the device performance. Simulation results lead to extremely steep slope characteristics endorsing its potential interest for ultralow power applications.