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Journal ArticleDOI

Asymmetric-Elevated-Source-Drain TFET: A Fairly Scalable and Reliable Device Architecture for Sub-400-mV Low-Stand-by-Power Digital Applications

TL;DR: In this paper, a silicon-based Asymmetric-Elevated-Source-Drain Tunnel Field Effect Transistor (AESD-TFET) for gate lengths (LGs), viz. 70, 45, 32, 22, and 13nm, is investigated for the first time.
Abstract: In this paper, silicon-based Asymmetric-Elevated-Source-Drain Tunnel Field-Effect Transistor (AESD-TFET), for gate lengths (LGs), viz. 70, 45, 32, 22, and 13 nm, is investigated for the first time ...
Citations
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DOI
TL;DR: In this article , an asymmetric U-shaped-gated tunnel FET (AU-TFET), with a unique vertical channel epilayer, at sub-7-nm technology node, has been proposed and investigated for its suitability to be a universal device.
Abstract: In this article, for the first time, an asymmetric U-shaped-gated tunnel FET (AU-TFET), with a unique vertical channel epilayer, at sub-7-nm technology node, has been proposed and investigated for its suitability to be a universal device. After validating the simulation scheme with the experimental results of fabricated TFET devices, the impact of thickness of the said epilayer ( ${T}_{\text {epi}}$ ), on device performance, has been thoroughly investigated in terms of a variety of performance metrics, both in analog and digital (Ana–Digi) domains. To increase the vitality of the work, the device-level analysis is stretched to the circuit level. The impact on the inverter performance, both in Ana–Digi domains, in terms of fundamental circuit performance parameters, viz., dc gain, short-circuit power dissipation during switching, noise margin (NM), and so on, has been studied, and ultimately, the most optimized TFET structure, in each domain, has been identified. Finally, in this whole device/circuit co-analysis, after summing up all the performance metrics in both the domains while looking for meeting the low-power (LP) requirements (following the goals, as applicable, of international roadmaps), altogether, we have found that AU-TFET with ${T}_{\text {epi}} $ = 6 nm could be considered as the ultimate optimized universal LP Ana–Digi TFET structure.

1 citations

Journal ArticleDOI
TL;DR: In this article , the impact of vertical channel epilayer thickness (Tepi) of a unique U-TFET has been investigated in the RF domain along with its linearity aspect.
Abstract: In this paper, the impact of vertical channel epilayer thickness (Tepi) of a unique U-TFET has been investigated in the RF domain along with its linearity aspect. Then, a glance has been thrown to the analog domain as well. The entire study has been carried out for the three low-power performance zones. After scrutinizing the linearity vs. analog/RF performance, it has been observed that the most enhanced device in the analog/RF domain is the worst performer with respect to the linearity aspect and vice-versa. This calls for optimization. The 6-nm-Tepi device turns out to be the one. Next, for the first time, a unique process-induced variation study in terms of the deviated Tepi from its optimized value has been introduced to find out the degree of sensitivity of different linearity parameters with respect to the deviation. Intriguingly, no single trend has been observed in terms of the dominance of linearity parameters for the said three zones – the result remains application specific.
References
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Journal ArticleDOI
17 Nov 2011-Nature
TL;DR: Tunnels based on ultrathin semiconducting films or nanowires could achieve a 100-fold power reduction over complementary metal–oxide–semiconductor transistors, so integrating tunnel FETs with CMOS technology could improve low-power integrated circuits.
Abstract: Power dissipation is a fundamental problem for nanoelectronic circuits. Scaling the supply voltage reduces the energy needed for switching, but the field-effect transistors (FETs) in today's integrated circuits require at least 60 mV of gate voltage to increase the current by one order of magnitude at room temperature. Tunnel FETs avoid this limit by using quantum-mechanical band-to-band tunnelling, rather than thermal injection, to inject charge carriers into the device channel. Tunnel FETs based on ultrathin semiconducting films or nanowires could achieve a 100-fold power reduction over complementary metal-oxide-semiconductor (CMOS) transistors, so integrating tunnel FETs with CMOS technology could improve low-power integrated circuits.

2,390 citations

Journal ArticleDOI
TL;DR: In this paper, a 70-nm n-channel tunneling field effect transistor (TFET) with sub-threshold swing (SS) of 52.8 mV/dec at room temperature was demonstrated.
Abstract: We have demonstrated a 70-nm n-channel tunneling field-effect transistor (TFET) which has a subthreshold swing (SS) of 52.8 mV/dec at room temperature. It is the first experimental result that shows a sub-60-mV/dec SS in the silicon-based TFETs. Based on simulation results, the gate oxide and silicon-on-insulator layer thicknesses were scaled down to 2 and 70 nm, respectively. However, the ON/ OFF current ratio of the TFET was still lower than that of the MOSFET. In order to increase the on current further, the following approaches can be considered: reduction of effective gate oxide thickness, increase in the steepness of the gradient of the source to channel doping profile, and utilization of a lower bandgap channel material

1,583 citations

Journal ArticleDOI
TL;DR: In this article, a double-gate tunnel field effect transistor (DG tunnel FET) with a high-kappa gate dielectric was proposed and validated using realistic design parameters, showing an on-current as high as 0.23 mA for a gate voltage of 1.8 V, an off-current of less than 1 fA (neglecting gate leakage), an improved average sub-threshold swing of 57 mV/dec, and a minimum point slope of 11 mV /dec.
Abstract: In this paper, we propose and validate a novel design for a double-gate tunnel field-effect transistor (DG tunnel FET), for which the simulations show significant improvements compared with single-gate devices using a gate dielectric. For the first time, DG tunnel FET devices, which are using a high-gate dielectric, are explored using realistic design parameters, showing an on-current as high as 0.23 mA for a gate voltage of 1.8 V, an off-current of less than 1 fA (neglecting gate leakage), an improved average subthreshold swing of 57 mV/dec, and a minimum point slope of 11 mV/dec. The 2D nature of tunnel FET current flow is studied, demonstrating that the current is not confined to a channel at the gate-dielectric surface. When varying temperature, tunnel FETs with a high-kappa gate dielectric have a smaller threshold voltage shift than those using SiO2, while the subthreshold slope for fixed values of Vg remains nearly unchanged, in contrast with the traditional MOSFET. Moreover, an Ion/Ioff ratio of more than 2 times 1011 is shown for simulated devices with a gate length (over the intrinsic region) of 50 nm, which indicates that the tunnel FET is a promising candidate to achieve better-than-ITRS low-standby-power switch performance.

1,230 citations

Journal ArticleDOI
TL;DR: Several of the extraction methods currently used to determine the value of threshold voltage from the measured drain current versus gate voltage transfer characteristics, focusing specially on single-crystal bulk MOSFETs are reviewed.

813 citations

Journal ArticleDOI
TL;DR: In this article, a detailed study of the doping-less tunnel field effect transistor (TFET) on a thin intrinsic silicon film using charge plasma concept was performed using calibrated simulations.
Abstract: Using calibrated simulations, we report a detailed study of the doping-less tunnel field effect transistor (TFET) on a thin intrinsic silicon film using charge plasma concept. Without the need for any doping, the source and drain regions are formed using the charge plasma concept by choosing appropriate work functions for the source and drain metal electrodes. Our results show that the performance of the doping-less TFET is similar to that of a corresponding doped TFET. The doping-less TFET is expected to be free from problems associated with random dopant fluctuations. Furthermore, fabrication of doping-less TFET does not require a high-temperature doping/annealing processes and therefore cuts down the thermal budget, opening up possibilities for fabricating TFETs on single crystal silicon-on-glass substrates formed by wafer scale epitaxial transfer.

433 citations