A steep-switching impact ionization-based threshold switching field-effect transistor

Kang, Chanwoo; Choi, Haeju; Son, Hyeonje; Kang, Taeho; Lee, Sang‐Min; Lee, Sungjoo

doi:10.1039/d2nr06547a

Cited by 6 publications

(3 citation statements)

References 34 publications

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“…Figure S2 shows the histogram of the hysteresis window of all-2D TS-FET in a cycle-to-cycle test (total of 75 cycles). The observed hysteresis window exerts a negligible effect on extra power consumption (Supporting Text 1, Figure S3), which could be further reduced by optimizing the structural design of the TS. , …”

Section: Resultsmentioning

confidence: 91%

All-2D-Materials Subthreshold-Free Field-Effect Transistor with Near-Ideal Switching Slope

Hu,

Li,

Chen

et al. 2024

ACS Nano

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The Boltzmann Tyranny, set by thermionic statistics, dictates the lower limit of switching slope (SS) of a MOSFET to be 60 mV/dec, the fundamental barrier for lowdissipative electronics. The large SS leads to nonscalable voltage, significant leakage, and power consumption, particularly at short channels, making transistor scaling an intimidating challenge. In recent decades, an array of steepslope transistors has been proposed; none is close to an ideal switch with ultimately abrupt switching (SS ∼ 0 mV/dec) between the binary logic states. We demonstrated an all-2D-materials van-der-Waals-heterostructure (vdW)-based FET that exhibits ultrasteep switching (0.33 mV/dec), a large on/off current ratio (∼10 7 ), and an ultralow off current (∼0.1 pA). The "Subthreshold-Free" operation achieved by the collective behavior of functional materials enables FET switching directly from the OFF-state to the ON-state with entirely eliminated subthreshold region, behaving as the ideal logic switch. Two-inch wafer-scale device fabrication is demonstrated. Boosted by device innovation and emerging materials, the research presents an advancement in achieving the "beyond-Boltzmann" transistors, overcoming one of the CMOS electronics' most infamous technology barriers that have plagued the research community for decades.

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Section: Resultsmentioning

confidence: 91%

All-2D-Materials Subthreshold-Free Field-Effect Transistor with Near-Ideal Switching Slope

Hu,

Li,

Chen

et al. 2024

ACS Nano

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“…[ 54–56 ] Recently, based on the unique properties of 2D materials such as in‐plane carrier transport and thickness‐dependent tunable bandgaps, excellent steep‐switching behaviors have been reported for various I 2 ‐FET structures. [ 57–61 ] We fabricated HfO 2 /HfSe 2 ‐based I 2 ‐FET with a separately controlled channel structure, as shown in Figure a. A top‐gate electrode was partially formed above the HfO 2 so that the HfSe 2 channel was divided into a gated‐region ( L gated ) controlled by the gate electrode and a short ungated‐region ( L ungated ≈110 nm) that was not covered by the gate dielectric (see Figure S24 in the Supporting Information for OM/scanning electron microscope (SEM) image of the device).…”

Section: Resultsmentioning

confidence: 99%

High‐κ Dielectric (HfO₂)/2D Semiconductor (HfSe₂) Gate Stack for Low‐Power Steep‐Switching Computing Devices

Kang,

Park,

Jung

et al. 2024

Advanced Materials

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Herein, we report a high‐quality gate stack (native HfO2 formed on 2D HfSe2) fabricated via plasma oxidation, realizing an atomically sharp interface with a suppressed interface trap density (Dit ∼ 5×1010 cm−2 eV−1). The chemically converted HfO2 exhibits dielectric constant, κ ∼ 23, resulting in low gate leakage current (∼10−3 A/cm2) at EOT ∼0.5 nm. Density functional calculations indicated that the atomistic mechanism for achieving a high‐quality interface is the possibility of O atoms replacing the Se atoms of the interfacial HfSe2 layer without a substitution energy barrier, allowing layer‐by‐layer oxidation to proceed. The field‐effect‐transistor‐fabricated HfO2/HfSe2 gate stack demonstrated an almost ideal subthreshold slope (SS) of ∼ 61 mV/dec (over four orders of IDS) at room temperature (300 K), along with a high Ion/Ioff ratio of ∼108 and a small hysteresis of ∼ 10 mV. Furthermore, by utilizing a device architecture with separately controlled HfO2/HfSe2 gate stack and channel structures, we fabricated an impact ionization FET that exhibited n‐type steep‐switching characteristics with an SS value of 3.43 mV/dec at room temperature, overcoming the Boltzmann limit. Our results provide a significant step toward the realization of post‐Si semiconducting devices for future energy‐efficient data‐centric computing electronics.This article is protected by copyright. All rights reserved

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“…It is a high-performance device that has gained considerable attention in the field of artificial intelligence calculations. The OTS enables switching only when the current value is above a certain level, to overcome the theoretical limit of the MOSFET [ 38 , 39 , 40 ]. In this study, an OTS device with a steep turn-on/off slope, high durability, low operating voltage, and a fast-switching speed of 100 ns was developed.…”

Section: Introductionmentioning

confidence: 99%

Improved Electrical Characteristics of Field Effect Transistors with GeSeTe-Based Ovonic Threshold Switching Devices

et al. 2023

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Hyper-field effect transistors (hyper-FETs) are crucial in the development of low-power logic devices. With the increasing significance of power consumption and energy efficiency, conventional logic devices can no longer achieve the required performance and low-power operation. Next-generation logic devices are designed based on complementary metal-oxide-semiconductor circuits, and the subthreshold swing of existing metal-oxide semiconductor field effect transistors (MOSFETs) cannot be reduced below 60 mV/dec at room temperature owing to the thermionic carrier injection mechanism in the source region. Therefore, new devices must be developed to overcome these limitations. In this study, we present a novel threshold switch (TS) material, which can be applied to logic devices by employing ovonic threshold switch (OTS) materials, failure control of insulator–metal transition materials, and structural optimization. The proposed TS material is connected to a FET device to evaluate its performance. The results demonstrate that commercial transistors connected in series with GeSeTe-based OTS devices exhibit significantly lower subthreshold swing values, high on/off current ratios, and high durability of up to 108.

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A steep-switching impact ionization-based threshold switching field-effect transistor

Abstract: A steep switching device with a low subthreshold swing (SS) that overcomes the fundamental Boltzmann limit (kT/q) is required to efficiently process a continuously increasing amount of data. Recently, two-dimensional...

Cited by 6 publications

References 34 publications

All-2D-Materials Subthreshold-Free Field-Effect Transistor with Near-Ideal Switching Slope

All-2D-Materials Subthreshold-Free Field-Effect Transistor with Near-Ideal Switching Slope

High‐κ Dielectric (HfO₂)/2D Semiconductor (HfSe₂) Gate Stack for Low‐Power Steep‐Switching Computing Devices

Improved Electrical Characteristics of Field Effect Transistors with GeSeTe-Based Ovonic Threshold Switching Devices

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A steep-switching impact ionization-based threshold switching field-effect transistor

Abstract: A steep switching device with a low subthreshold swing (SS) that overcomes the fundamental Boltzmann limit (kT/q) is required to efficiently process a continuously increasing amount of data. Recently, two-dimensional...

Cited by 6 publications

References 34 publications

All-2D-Materials Subthreshold-Free Field-Effect Transistor with Near-Ideal Switching Slope

All-2D-Materials Subthreshold-Free Field-Effect Transistor with Near-Ideal Switching Slope

High‐κ Dielectric (HfO2)/2D Semiconductor (HfSe2) Gate Stack for Low‐Power Steep‐Switching Computing Devices

Improved Electrical Characteristics of Field Effect Transistors with GeSeTe-Based Ovonic Threshold Switching Devices

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High‐κ Dielectric (HfO₂)/2D Semiconductor (HfSe₂) Gate Stack for Low‐Power Steep‐Switching Computing Devices