scholarly journals Improving ESD Protection Robustness Using SiGe Source/Drain Regions in Tunnel FET

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 657 ◽  
Author(s):  
Zhaonian Yang ◽  
Yuan Yang ◽  
Ningmei Yu ◽  
Juin Liou

Currently, a tunnel field-effect transistor (TFET) is being considered as a suitable electrostatic discharge (ESD) protection device in advanced technology. In addition, silicon-germanium (SiGe) engineering is shown to improve the performance of TFET-based ESD protection devices. In this paper, a new TFET with SiGe source/drain (S/D) regions is proposed, and its ESD characteristics are evaluated using technology computer aided design (TCAD) simulations. Under a transmission line pulsing (TLP) stressing condition, the triggering voltage of the SiGe S/D TFET is reduced by 35% and the failure current is increased by 17% in comparison with the conventional Si S/D TFET. Physical insights relevant to the ESD enhancement of the SiGe S/D TFET are provided and discussed.

In this paper, a novel heterojunction tunnel field-effect transistor (HTFET) using Sentaurus technology computer-aided design (TCAD) simulations has been presented. The InAs/GaSb compound materials are used in both single gate heterojunction TFET (SG-HTFET) and Double gate heterojunction TFET (DG-HTFET) with SiO2 gate oxide layer to increase performance of the device.The implemented SG-HTFET and DG-HTFET device are increase the TFET's cross-sectional tunnel area. This result develops the subthreshold swing (SS) by 2.45 times, drive current (ION) is close to 10-6 A/µm, leakage current (IOFF) is close to 10-17 A/µm and also diminish the ambipolarity of the device compared to the TFET.


Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 128
Author(s):  
Zhihua Zhu ◽  
Zhaonian Yang ◽  
Xiaomei Fan ◽  
Yingtao Zhang ◽  
Juin Jei Liou ◽  
...  

The tunnel field-effect transistor (TFET) is a potential candidate for replacing the reverse diode and providing a secondary path in a whole-chip electrostatic discharge (ESD) protection network. In this paper, the ESD characteristics of a traditional point TFET, a line TFET and a Ge-source TFET are investigated using technology computer-aided design (TCAD) simulations, and an improved TFET-based whole-chip ESD protection scheme is proposed. It is found that the Ge-source TFET has a lower trigger voltage and higher failure current compared to the traditional point and line TFETs. However, the Ge-source TFET-based secondary path in the whole-chip ESD protection network is more vulnerable compared to the primary path due to the low thermal instability. Simulation results show that choosing the proper germanium mole fraction in the source region can balance the discharge ability and thermal failure risk, consequently enhancing the whole-chip ESD robustness.


In this paper, DC performance of double gate tunnel field effect transistor with heterojunction has been assessed by various III-V compound semiconductor materials using 2-D Technology Computer Aided Design (TCAD) simulations. Different hetero high-κ dielectric materials like HfO2 , ZrO2 have been incorporated to achieve better electrical characteristics, viz. high ON-state current drivability, improved switching ratio and high tunneling probability. In this work, lower band gap materials have been used as hetero gate dielectric to enhance mobility using band to band tunneling (BTBT), transconductance and steeper subthreshold-slope. The heterojunction TFET (HTFET) then incorporated with various hetero dielectrics (high-κ and low-κ combination), where the ZrO2 – SiO2 combination of dielectric having thickness of 2 nm both in front and back gate, attains maximum value of ION as 1.522 × 10-5 A/µm. The subthreshold swing (ss) has also been recorded best as 23.93 mV/dec in comparison with conventional homo dielectric i.e. SiO2 -SiO2 oxide throughout the 50 nm channel of HTFET as 34.22 mV/dec, can serve as better alternative tunnel FETs in low power logic applications.


Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 749 ◽  
Author(s):  
Jang ◽  
Yoon ◽  
Cho ◽  
Jung ◽  
Lee ◽  
...  

In this paper, a germanium-based gate-metal-core vertical nanowire tunnel field effect transistor (VNWTFET) has been designed and optimized using the technology computer-aided design (TCAD) simulation. In the proposed structure, by locating the gate-metal as a core of the nanowire, a more extensive band-to-band tunneling (BTBT) area can be achieved compared with the conventional core–shell VNWTFETs. The channel thickness (Tch), the gate-metal height (Hg), and the channel height (Hch) were considered as the design parameters for the optimization of device performances. The designed gate-metal-core VNWTFET exhibits outstanding performance, with an on-state current (Ion) of 80.9 μA/μm, off-state current (Ioff) of 1.09 × 10−12 A/μm, threshold voltage (Vt) of 0.21 V, and subthreshold swing (SS) of 42.8 mV/dec. Therefore, the proposed device was demonstrated to be a promising logic device for low-power applications.


Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 30 ◽  
Author(s):  
Jang Hyun Kim ◽  
Hyun Woo Kim ◽  
Garam Kim ◽  
Sangwan Kim ◽  
Byung-Gook Park

In this paper, a novel tunnel field-effect transistor (TFET) has been demonstrated. The proposed TFET features a SiGe channel, a fin structure and an elevated drain to improve its electrical performance. As a result, it shows high-level ON-state current (ION) and low-level OFF-state current (IOFF); ambipolar current (IAMB). In detail, its ION is enhanced by 24 times more than that of Si control group and by 6 times more than of SiGe control group. The IAMB can be reduced by up to 900 times compared with the SiGe control group. In addition, technology computer-aided design (TCAD) simulation is performed to optimize electrical performance. Then, the benchmarking of ON/OFF current is also discussed with other research group’s results.


2020 ◽  
Vol 20 (7) ◽  
pp. 4298-4302
Author(s):  
Ryoongbin Lee ◽  
Junil Lee ◽  
Kitae Lee ◽  
Soyoun Kim ◽  
Sihyun Kim ◽  
...  

In this paper, we propose an I-shaped SiGe fin tunnel field-effect transistor (TFET) and use technology computer aided design (TCAD) simulations to verify the validity. Compared to conventional Fin TFET on the same footprint, a 27% increase in the effective channel width can be obtained with the proposed TFET. The proposed Fin TFET was confirmed to have 300% boosted on-current (I on), 25% reduced subthreshold swing (SS), and 52% lower off-current (I off) than conventional Fin TFET through TCAD simulation results. These performance improvements are attributed to increased effective channel width and enhanced gate controllability of the I-shaped fin structure. Furthermore, the fabrication process of forming an I-shaped SiGe fin is also presented using the SiGe wet etch. By optimizing the Ge condensation process, an I-shaped SiGe fin with a Ge ratio greater than 50% can be obtained.


2020 ◽  
Vol 10 (9) ◽  
pp. 3054
Author(s):  
Hyun Woo Kim ◽  
Daewoong Kwon

Tunnel field-effect transistor (Tunnel FET) with asymmetric spacer is proposed to obtain high on-current and reduced inverter delay simultaneously. In order to analyze the proposed Tunnel FET, electrical characteristics are evaluated by technology computer-aided design (TCAD) simulations with calibrated tunneling model parameters. The impact of the spacer κ values on tunneling rate is investigated with the symmetric spacer. As the κ values of the spacer increase, the on-current becomes enhanced since tunneling probabilities are increased by the fringing field through the spacer. However, on the drain-side, that fringing field through the drain-side spacer increases ambipolar current and gate-to-drain capacitance, which degrades leakage property and switching response. Therefore, the drain-side low-κ spacer, which makes the low fringing field, is adapted asymmetrically with the source-side high-κ spacer. This asymmetric spacer results in the reduction of gate-to-drain capacitance and switching delay with the improved on-current induced by the source-side high-κ spacer.


Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 780
Author(s):  
Jang Hyun Kim ◽  
Hyun Woo Kim ◽  
Young Suh Song ◽  
Sangwan Kim ◽  
Garam Kim

In this paper, an investigation is performed to analyze the L-shaped tunnel field-effect transistor (TFET) depending on a gate work function variation (WFV) with help of technology computer-aided design (TCAD) simulation. Depending on the gate voltage, the three variations occur in transfer curves. The first one is the on-state current (ION) variation, the second one is the hump current (IHUMP) variation, and the last one is ambipolar current (IAMB) variation. According to the simulation results, the ION variation is sensitive depending on the size of the tunneling region and could be reduced by increasing the tunneling region. However, the IHUMP and IAMB variations are relatively irrelevant to the size of the tunneling region. In order to analyze the cause of this difference, we investigated the band-to-band tunneling (BTBT) rate according to WFV cases. The results show that when ION is formed in L-shaped TFET, the BTBT rate relies on the WFV in the whole region of the gate because the tunnel barrier is formed in the entire area where the source and the gate meet. On the other hand, when the IHUMP and IAMB are formed in L-shaped TFET, the BTBT rate relies on the WFV in the edge of the gate.


2020 ◽  
Vol 20 (7) ◽  
pp. 4182-4187
Author(s):  
Ye Sung Kwon ◽  
Seong-Hyun Lee ◽  
Yoon Kim ◽  
Garam Kim ◽  
Jang Hyun Kim ◽  
...  

The tunnel field-effect transistor (TFET) with surrounding channel nanowire (SCNW) structure promises better performance than the conventional planar TFET in terms of subthreshold swing (SS) and on-current (ION). In spite of the advantages of SCNW TFET, there are some technical issues in the aspects of a hump phenomenon in subthreshold region and a high ambipolar current (IAMB) in off-state. In order to overcome these issues, a novel dual-gate SCNW TFET (DG-SCNW TFET) with differential gate work functions (WFs) and a gate-drain underlap is proposed and studied by using technology computer-aided design (TCAD) simulation. In addition, a hetero-junction with SiGe source is applied to improve the device performance. Finally, it is confirmed that the optimized DG-SCNW TFET shows the remarkable performance comparing with the control device.


Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 760 ◽  
Author(s):  
Seunghyun Yun ◽  
Jeongmin Oh ◽  
Seokjung Kang ◽  
Yoon Kim ◽  
Jang Hyun Kim ◽  
...  

In this report, a novel tunnel field-effect transistor (TFET) named ‘F-shaped TFET’ has been proposed and its electrical characteristics are analyzed and optimized by using a computer-aided design simulation. It features ultra-thin and a highly doped source surrounded by lightly doped regions. As a result, it is compared to an L-shaped TFET, which is a motivation of this work, the F-shaped TFET can lower turn-on voltage (VON) maintaining high on-state current (ION) and low subthreshold swing (SS) with the help of electric field crowding effects. The optimized F-shaped TFET shows 0.4 V lower VON than the L-shaped TFET with the same design parameter. In addition, it shows 4.8 times higher ION and 7 mV/dec smaller average SS with the same VON as that for L-shaped TFET.


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