• Journal of information and communication convergence engineering
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• v.19 no.4
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• pp.263-268
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• 2021

Although the compact capacitance model of point tunneling types of tunneling field-effect transistors (TFET) has been proposed, those of line tunneling types of TFETs have not been reported. In this study, a compact capacitance model of an L-shaped TFET (LTFET), a line tunneling type of TFET, is proposed using the previously developed surface potentials and current models of P- and L-type LTFETs. The Verilog-A LTFET model for simulation program with integrated circuit emphasis (SPICE) was also developed to verify the validation of the compact LTFET model including the capacitance model. The SPICE simulation results using the Verilog-A LTFET were compared to those obtained using a technology computer-aided-design (TCAD) device simulator. The current-voltage characteristics and capacitance-voltage characteristics of N and P-LTFETs were consistent for all operational bias. The voltage transfer characteristics and transient response of the inverter circuit comprising N and P-LTFETs in series were verified with the TCAD mixed-mode simulation results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.241-242
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• 2017

Part of the channel in L-shaped tunnel field-effect transistor (LTFET) is very thin and suffers from quantum confinement effect. Role of quantum confinement effect on band-to-band-tunneling (BTBT) of LTFET was investigated using numerical simulation and band diagram analysis. It was found that quantum confinement effect significantly affects the BTBT mechanism of LTFET devices.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.6
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• pp.551-555
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• 2013

Linearity characteristics of hetero-gate-dielectric tunneling field-effect transistors (HG TFETs) have been compared with those of high-k-only and $SiO_2$-only TFETs in terms of IIP3 and P1dB. It has been observed that the optimized HG TFETs have higher IIP3 and P1dB than high-k-only and $SiO_2$-only TFETs. It is because HG TFETs show higher transconductance ($g_m$) and current drivability than $SiO_2$-only TFETs and $g_m$ less sensitive to gate voltage than high-k-only TFETs.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.2
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• pp.230-238
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• 2017

We have proposed an InGaAs-based gate-all-around (GAA) tunneling field-effect transistor (TFET) with a stacked dual-metal gate (DMG). The electrical performances of the proposed TFET are evaluated through technology computer-aided design (TCAD) simulations. The simulation results show that the proposed TFET demonstrates improved DC performances including high on-state current ($I_{on}$) and steep subthreshold swing (S), in comparison with a single-metal gate (SMG) TFET with higher gate metal workfunction, as it has a thinner source-channel tunneling barrier width by low workfunction of source-side channel gate. The effects of the gate workfunction on $I_{on}$, the off-state current ($I_{off}$), and S in the DMG-TFETs are examined. The DMG-TFETs with PNPN structure demonstrate outstanding DC performances and RF characteristics with a higher n-type doping concentration in the $In_{0.8}Ga_{0.2}As$ source-side channel region.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.787-791
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• 2004

We investigated field-effect ion-transport devices based on carbon nanotubes by using classical molecular dynamics simulations under applied external force fields, and we present model schematics that car be applied to the nanoscale data storage devices and unipolar ionic field-effect transistors. As the applied external force field is increased, potassium ions rapidly flow through the nanochannel. Under low external force fields, ther nal fluctuations of the nanochannels affect tunneling of the potassium ions whereas the effects of thermal fluctuations are negligible under high external force fields. Since the electric current conductivity increases when potassium ions are inserted into fullerenes or carbon nanotubes, the field effect due to the gate, which can modify the position of the potassium ions, changes the tunneling current between the drain and the source.

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.5
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• pp.572-578
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• 2014

In order to overcome small current drivability of a tunneling field-effect transistor (TFET), a TFET using Schottky barrier (SBTFET) is proposed. The proposed device has a metal source region unlike the conventional TFET. In addition, dopant segregation technology between the source and channel region is applied to reduce tunneling resistance. For TFET fabrication, spacer technique is adopted to enable self-aligned process because the SBTFET consists of source and drain with different types. Also the control device which has a doped source region is made to compare the electrical characteristics with those of the SBTFET. From the measured results, the SBTFET shows better on/off switching property than the control device. The observed drive current is larger than those of the previously reported TFET. Also, short-channel effects (SCEs) are investigated through the comparison of electrical characteristics between the long- and short-channel SBTFET.

• Journal of Electrical Engineering and Technology
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• v.9 no.6
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• pp.2070-2078
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• 2014

In this work, the frequency response of gate-all-around (GAA) Ge/GaAs heterojunction tunneling field-effect transistor (TFET) with hetero-gate-dielectric (HGD) and pnpn channel doping profile has been analysed by technology computer-aided design (TCAD) device-circuit mixed-mode simulations, with comparison studies among ppn, pnpn, and HGD pnpn TFET devices. By recursive tracing of voltage transfer curves (VTCs) of a common-source (CS) amplifier based on the HGD pnpn TFET, the operation point (Q-point) was obtained at $V_{DS}=1V$, where the maximum available output swing was acquired without waveform distortion. The slope of VTC of the amplifier was 9.21 V/V (19.4 dB), which mainly resulted from the ponderable direct-current (DC) characteristics of HGD pnpn TFET. Along with the DC performances, frequency response with a small-signal voltage of 10 mV has been closely investigated in terms of voltage gain ($A_v$), unit-gain frequency ($f_{unity}$), and cut-off frequency ($f_T$). The Ge/GaAs HGD pnpn TFET demonstrated $A_v=19.4dB$, $f_{unity}=10THz$, $f_T=0.487$ THz and $f_{max}=18THz$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.616-618
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• 2016

Four types of structure of tunnel field-effect transistors (TFETs) have been investigated by TCAD simulation. Pocket and L-shaped TFETs are better performance than single-gate and double-gate TFETs in terms of on-current and subthreshold swing. New guideline of TFETs is presented for the structure design.

• Journal of the Semiconductor & Display Technology
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• v.5 no.1 s.14
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• pp.21-25
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• 2006

To improve the performance of organic thin film transistor, we investigated the properties of gate insulator's surface according to the leakage current by I-V measurement. The surface was treated by the dilute n-octadecyltrichlorosilane solution. The alkyl group of n-octadecyltrichlorosilane induced the electron tunneling and the electron tunneling current caused the breakdown at high electric field, consequently shifting the breakdown voltage. The 0.5% sample with an electron-rich group was found to have a large leakage current and a low barrier height because of the effect of an energy barrier lowered by, thermionic current, which is called the Schottky contact. The surface properties of the insulator were analyzed by I-V measurement using the effect of Poole-Frankel emission.

• Journal of IKEEE
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• v.23 no.2
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• pp.704-709
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• 2019

In this paper, the electrical characteristics of tunneling field effect transistor(TFET) was studied for different annealing conditions. The TFET samples annealed using hydrogen forming gas(4 %) and Deuterium($D_2$) forming gas(4 %). All the measurements were conducted in noise shielded environment. The results show that subthreshold slope(SS) decreased by 33 mV/dec after annealing process compared to before annealing. Under various temperature range, the noise is improved by average of 31.2 % for 10 atm Deuterium gas at $V_G=3V$ condition. It is also noticed that, post metal annealing with $D_2$ gas reduces the noise by average of 30.7 % at $I_D=100nA$ condition.