Gate Tunnel Field Effect Transistor Research Articles

Algorithm prediction of single particle irradiation effect based on novel TFETs

In order to predict the single particle irradiation of tunnel field effect transistor (TFET) devices, a deep learning algorithm network model was built to predict the key characterization parameters of the single particle transient. Computer aided design (TCAD) technique is used to study the influence of single particle effect on the novel stacked source trench gate TFET device. The results show that with the increase of drain voltage, incident width of heavy ions (less than 0.04μm), and linear energy transfer, the drain transient current and collected charge also increase. The prediction results of deep learning algorithm show that the relative error percentage of drain current pulse peak (IDMAX) and collected charge (Qc) is less than 10%, and the relative error percentage of most predicted values is less than 1%. Comparison experiments with five traditional machine learning methods (support vector machine, decision tree, K-nearest algorithm, ridge regression, linear regression) show that the deep learning algorithm has the best performance and has the smallest average error percentage. This data-driven deep learning algorithm model not only enables researchers who are not familiar with semiconductor devices to quickly obtain the transient data of a single particle under any conditions; at the same time, it can be applied to digital circuit design as a data-driven device model reflecting the reliability of single particle transient. The application of deep learning in the field of device irradiation prediction has a highly promising prospect in the future.

Steep subthreshold swing Double - Gate tunnel FET using source pocket engineering: Design guidelines

In this work, we propose a promising source engineered Double - Gate (DG) Tunnel Field Effect Transistor (TFET) device capable of providing remarkably low value of Subthreshold Swing (SS) with sufficiently high drive current. Using Sentaurus TCAD simulations, we demonstrate that counter-doped horizontal pockets (doping of pocket is kept opposite to that of source) when placed in the source region introduces a built-in band bending at the source-pocket junction. This lowers the minima of Conduction Band (CB) in pocket region thereby reducing the barrier width as the pocket CB moves closer to source Valence Band (VB). As a result, stronger electric field is observed thereby reducing the threshold voltage (onset of band-to-band tunneling (BTBT)) and subsequent reduction in subthreshold swing. To boost the ON-current and suppress ambipolarity, high-k dielectric material along with low work-function gate material is introduced at source side and low-k gate dielectric along with high work-function gate material is introduced at drain side. Compared to point tunneling in conventional TFETs, the gate overlapped pockets in the proposed structure result in an increase in cross-section area available for BTBT thereby leading to line tunneling of carriers from the source to the pocket, resulting in higher ON-current. In this work, we discuss the role of source engineering in boosting the performance of Hetero-Dielectric (HD) Dual-Metal-Double-Gate (DMDG) TFET. We provide design guidelines to achieve steeper subthreshold swing while considering pocket doping and pocket thickness as the key parameters. A comparative study of conventional DG-TFET and HD-DG-TFET with the proposed Gate-over-Pockets (GoP) HD-DMDG-TFET structure is done. When compared to the conventional DG-TFET with same geometrical parameters, the proposed structure provides ∼33× steeper SS, more than two order improved ON-current, two order lower ambipolar current and 133 folds better Ion/Ioff thus becomes the perfect choice for low power applications.

GaSb/Si Heterojunction Based Pocket Engineered Vertical Non-Uniform Channel Double Gate TFETs for Low Power Applications

This article compares the performance of two Vertical Non-Uniform Channel Double Gate Tunnel Field Effect Transistors (VNUCDGTFETs), a normal all-Silicon Tunnel Field-Effect Transistor (TFET) having a pocket and another one a Gallium Antimonide/Silicon heterojunction TFET with pocket. GaSb is a III-V narrow energy band gap material, employed in the source area of the TFET structure to decrease the tunneling width and thus to make more number of carriers capable enough to tunnel through the heterojunction. The proposed source pocket heterojunction non uniform channel TFET presents superior performance as compared to the conventional non uniform channel vertical TFET with a pocket, regarding a larger ION/IOFF ratio, a reduced sub-threshold swing, and a smaller threshold voltage at VDS = 0.5 V. Furthermore, the proposed TFET device undergoes a comprehensive analysis of both DC parameters and various analog/RF parameters.

Performance and reliability assessment of source work function engineered charge plasma based Ti/HfO2/Al2O3/Ge, double gate TFET

The Tunnel Field Effect Transistor (TFET) often suffers from low ON current (I ON), charge traps, and thermal variability, which limits its performance and reliability. To address these issues, the source work function engineered Ge Charge Plasma Double Gate Tunnel Field Effect Transistor (CP-DGTFET) device structure with HfO2/Al2O3 bilayer gate dielectric is designed and investigated using numerical TCAD simulations. The proposed Ti/HfO2/Al2O3/Ge CP-DGTFET device structure showed excellent DC characteristics with exceptional I ON, I ON/I OFF ratio, and minimal sub-threshold swing (S) of ∼3.04 × 10−4 A μm−1, ∼1.2 × 1010, and ∼3.4 mV/dec, respectively. Furthermore, the device’s analog characteristics displayed good transconductance, cut-off frequency, and gain bandwidth product of ∼0.75 mS/μm, ∼0.97 THz, and ∼102 GHz, respectively. Moreover, the charge trap exploration divulges that positive ITCs can enhance device performance, whereas negative ITCs can adversely impact the electrical characteristics of CP-DGTFET. Additionally, the temperature-dependent analysis showed that the OFF-state leakage current increases from ∼1.7 × 10−15 A μm−1 to 2.4 × 10−10 A μm−1 with temperature fluctuations from 275 K to 375 K. Overall, the work function-engineered CP-based Ti/HfO2/Al2O3/Ge DGTFET device structure shows great potential for improving the performance and reliability of Ge TFET technology.

Circuit Level Implementation of Negative Capacitance Source Pocket Double Gate Tunnel FET for Low Power Applications

This manuscript presents a pioneering study on enhancing analog and radio frequency performance through the implementation of negative capacitance source pocket double gate tunnel field-effect transistor. By integrating a ferroelectric material into the gate stack and introducing a fully depleted n-type pocket near the source/channel junction, we achieved significant enhancements in key metrics such as ON current (ION), switching ratio, subthreshold swing (SS), and various analog/RF parameters like transconductance (gm), cutoff frequency (fT) when compared to existing literature. Additionally, we extend our analysis to circuit-level applications such as inverter and 5-stage ring oscillator. Our findings reveal an impressive inverter delay of 1.09 ps with a gain of 104, as well as a ring oscillator operating at a frequency of 500 GHz. These results position the proposed device as an ideal candidate for high-speed, low-power applications.

Design and Evaluation of a Double-Gate Tunnel Field Effect Transistor for the Detection of Breast Cancer Cells

This research paper investigates the application of a Double Gate (DG) Tunnel Field-Effect Transistor (DG-TFET) for the detection of cell lines derived from breast cancer tissue, namely Hs578T, MDA-MB-231, MCF-7, and T47D. The device incorporates two nanocavities positioned beneath the two gate electrodes, significantly enhancing detection capabilities. The study emphasizes the differentiation between healthy non-tumorigenic cells (MCF-10A) and breast cancer-derived cell lines by incorporating gate engineering into the TFET. Furthermore, the research explores the impact of changes in dielectric values specific to different breast malignant cell types on the biosensor's detection capabilities. Additionally, the investigation delves into the influence of variations in device geometry, including cavity dimensions and dielectric layer thickness, on critical parameters such as drain current sensitivity, transconductance sensitivity, and ION/IOFF sensitivity. Sensitivity analysis concerns drive current, ION/IOFF ratio, threshold voltage (Vth), and transconductance. The structural design of the device is tailored to facilitate array-based diagnosis and screening of cell lines derived from breast cancer tissue. This design offers several advantages, including a simplified transduction process, compatibility with CMOS processes, cost-effectiveness, reproducibility, and adjustable electrical responses. The researchers employed ATLAS, a two-dimensional (2D) device simulator from Silvaco, to model and define the device structure. The numerical simulations validate the device's performance, demonstrating favorable ON-OFF transition profiles.

A Mg2Si/Si heterojunction based dielectric modulated dopingless TFET biosensor for label free detection

In this work, we contrasted the potential of Mg2Si/Si heterojunction-based dopingless (DL) double gate tunnel field effect transistor (DGTFET) with conventional (C)-DL-DGTFET. The simulation results exhibit excellent capabilities of Mg2Si source DL-DGTFET in terms of electrical properties, that are ION, ION/IOFF, electron tunnelling rate, Vth and SS in comparison to C-DL-TFET. A remarkable improvement of 77.5 % and 81.3 % is observed while computing Vth and SS, in the case of Mg2Si source DL-DGTFET. For that reason, to avail most advantage of Mg2Si/Si heterojunction, the proposed device with similar specifications and dimensions is critically analysed for biosensing applications. Dual cavities (20 nm x 5 nm) are carved underneath gate electrodes near source channel junction to grab the biomolecules. The proposed biosensor (Mg2Si source DL-DGTFET) exhibits significant sensitivity results for both charged (deoxyribonucleic acid (DNA)) and uncharged (neutral) biomolecules. Also, we have reported an impact on biosensor sensitivity with variation in the height of nanocavity (tbio). The effect of steric hindrance on sensitivity is analysed by considering four step profiles - increasing, decreasing, convex and concave. The result reveals the competency of Mg2Si/Si heterojunction DL-DGTFET in terms of overall device sensitivity.

Gate Oxide Thickness and Drain Current Variation of Dual Gate Tunnel Field Effect Transistor

Gate Oxide Thickness and Drain Current Variation of Dual Gate Tunnel Field Effect Transistor

High Sensitivity of Dielectrically Modulated Tunnel Field Effect Transistor for Biosensor Applications.

The Dielectrically Modulated Full Gate Tunnel Field Effect Transistor (FET) with dual nanocavities, as described in the paper, is a novel device designed as a label-free biosensor for detecting cancer cell biomolecules. This biosensor utilizes the principles of field-effect transistors and incorporates nanocavities to enhance the detection sensitivity. The simulations are conducted using the Silvaco Atlas model, which allowed for the analysis of the device's electrical characteristics in the presence of various cancer cell biomolecules. The performance of the proposed device is evaluated using several sensing metrics, including current, threshold voltage, and subthreshold slope. These metrics are examined to assess their sensitivity to the presence of different cancer cell biomolecules. By analyzing these electrical characteristics, we can able to determine the device's ability to detect and differentiate between specific biomolecules associated with cancer cells. One important aspect discussed in the paper is the incorporation of nanocavities in the device design. These nanocavities have a significant impact on enhancing the sensing capabilities of the biosensor. The paper also introduces the concept of the filling factor parameter, which describes the fraction of the nanocavity volume occupied by the cancer cell biomolecules. This parameter plays a crucial role in achieving optimal sensing performance. Overall, the paper presents a comprehensive analysis of the proposed Dielectrically Modulated Full gate Tunnel FET embedded with dual nanocavities as a label-free biosensor for cancer cell biomolecules. The simulations conducted using the Silvaco Atlas model provide valuable insights into the device's electrical characteristics and its sensitivity to different biomolecules. The study emphasizes the significance of nanocavities and their filling factor parameter in achieving enhanced sensing performance for cancer cell detection.

Design and Analysis of Symmetrical Dual Gate Tunnel Field Effect Transistor with Gate Dielectric Materials in 10nm Technology

Design and Analysis of Symmetrical Dual Gate Tunnel Field Effect Transistor with Gate Dielectric Materials in 10nm Technology

Electrical characteristics assessment and noise analysis of pocket-doped multi source T-shaped gate tunnel FET

A detailed analysis of a novel multi-source T-shaped gate Tunnel FET (MS-TTFET) is presented in this study in order to address the main issues with conventional TFETs. Due to its exceptionally low off-state current (IOFF) and remarkable sub-threshold properties, the tunnel field effect transistor has received a great deal of interest for low standby power applications. The MSR's integration into the SOI platform increases the device's on current, which increases the effective tunnelling area in the middle of the source-channel junctions. An isolator oxide has been added to prevent the source and drain regions from being directly coupled. A SiGe pocket has been suggested at the source and channel junction; silicon-germanium, a low bandgap material which enhances the tunnelling of charge carriers. A T-shaped gate can increase the effectiveness of the tunnel junction in order to limit the lower value of the leakage current. The multi-source regions of the T-shaped gate tunnel field effect transistor can boost the on-state current (ION) by improving tunnel junction areas. The device's ION/IOFF ratio, which is 1013 for our suggested construction, is the standard measure of merit for any device. It is possible to achieve an increased ON current of the order of 10−5 A/μm with a negligible subthreshold swing (SS) of 42 mV/decade. Moreover, the effect of low frequency flicker noise on the device behavior has been investigated.

Analytical modelling and reliability analysis of charge plasma-assisted Mg2Si/Si heterojunction doping less DGTFET for low-power switching applications

Fabrication of tunnel field effect transistor (TFET) confronts various challenges, one of which is random dopant fluctuation (RDF), which diminishes the benefits associated with low subthreshold swing (SS) and high ION/IOFF ratio. By conducting physics-based 2D analytical modelling, this paper proposes a magnesium silicide/silicon (Mg2Si/Si) heterojunction-based doping less double gate tunnel field effect transistor (HB-DL-DGTFET). This work utilizes the concept of charge plasma to tackle the issues of RDF. The analytical analysis in this study is based upon the determination of the center-channel potential by solving 2D Poisson’s equation, considering appropriate boundary conditions. Here, surface potential, electric field, energy bands, drain current and threshold voltage are extracted mathematically. In addition to the aforementioned parameters, several other analog performance parameters like transconductance, drain conductance, device efficiency, intrinsic gain, output resistance and channel resistance have also been studied in this context. The analytical findings have been duly validated using the ATLAS TCAD device simulator. Furthermore, this work focuses on exploring proposed device reliability through an investigation of, the influence of interface trap charges (ITC), present at the Si/SiO2 interface. The study analyses ITC's impact on analog performance and the obtained results are compared with that of conventional doping less DGTFET (C-DL-DGTFET). The simulation results reveal that HB-DL-DGTFET exhibits greater immunity against ITC. Thus, validating the potential of HB-DL-DGTFET as a superior candidate for low-power switching applications.

Simulation of Dual-Material Hetero-Double Gate Tunnel Field Effect Transistor (TFET) in Sub-Micron Region

To meet the performance requirements of low power mobile devices, a device with a high ION/IOFF ratio at low-VDD is needed. TFETs are gaining popularity due to their low subthreshold slope and high transconductance compared to MOSFETs. However, silicon-based TFETs have low on-state current, which limits their use in high-performance applications. To overcome this limitation, using a narrower band gap material like Ge can increase tunneling efficiency at the source side. Additionally, the larger ambipolar current associated with Si-TFETs can be reduced by considering a dual-material hetero-double-gate-dielectric (DM HDG) TFET. The main objective of this research is to propose and characterize a new TFET structure by considering the advantages associated with hetero structure and hetero-gate-dielectric TFETs, which realizes a device with an enhanced ION and a suppressed ambipolar current. The structure was fabricated with the addition of a hetero-dielectric Buried Oxide (BOX) on the doped substrate for the reduction of ambipolar current. We will adopt source-to-gate overlap technique to achieve desired subthreshold slope (SS). All the simulations were done by using 2-D TCAD simulator by Atlas Silvaco. The structure was optimized in terms of (ION/IOFF) and other performance metrics and simulation results were compared with other available structures in the literature.

InN TFET with extended gate for high sensitivity label‐free biosensor

AbstractAn extended gate tunneling field effect transistor (EG‐TFET) with narrow bandgap material InN as a label‐free dielectric modulated biosensor is proposed and investigated. An optimum structure of the proposed InN TFET is given by comparing on‐state and ambipolar current. The on‐state current is improved by increasing the length of source overlap, for the rate of forward tunneling increases. Further, the ambipolar current is suppressed by increasing the length of drain offset, for the rate of backward tunneling decreases. A cavity under the gate electrode is formed for sensing biomolecules by dielectric modulation. The performance of EG‐TFET biosensor corresponding to varied dielectric constants of biomolecule is analyzed. In addition, the impacts of charge density and partial filled cavity on the drain current sensitivity are investigated. The electric field, surface potential and energy band profiles are used to explain the working principle of the EG‐TFET biosensor. The simulations reveal that the drain current sensitivity is 3.72 × 107 when neutral biomolecule with κ = 12 is immobilized in the cavity. A linearity fit verification is given, and the results of current sensitivity reveal a good linearity of the EG‐TFET biosensor with fitness coefficient γ2 > 0.99.

Analytical drain current model development of twin gate TFET in subthreshold and super threshold regions

In this work, an analytical model for a twin gate Tunnel Field Effect Transistor's drain current operating in the subthreshold and superthreshold regions is proposed. Using this drain current model, the ratio of transconductance to drain current, a crucial metric for the integrated analog circuit design technique, has been retrieved. Due to the simplicity of this approach, it may be quickly implemented for any type of dual gate TFETs by adjusting a few parameters. Comparing the drain current calculated by this analytical model to the drain current simulated by the 2D-Sentaurus TCAD software demonstrates the Tunnel FET's authenticity. The proposed analytical method can be used to achieve the appropriate transconductance for operating Tunnel FETs in the gigahertz region with very low milliwatt power consumption.

Pocketed dual metal gate TFET: Design and simulation

In this work, design and simulation of two novel tunnel field effect transistors with improved DC and radio frequency (RF) performance has been conducted. The first proposed tunnel field effect transistor (TFET) employs a highly doped n + pocket in the intrinsic channel along with a combination of stacked oxide (silicon dioxide and hafnium oxide). This configuration helps in the enhancement of tunneling at the source/channel junction, thereby improving parameters like ON-current (ION), average subthreshold slope (SS avg) and ION/IOFF. The structure is modified further by employing a dual metal gate, having different work-functions, in addition to dual stacked oxide. The gate near the source, called as the tunneling gate, has a work function of 4.3 eV and a gate near the drain side, called as the auxiliary gate, has a work-function of 4.7 eV. This second proposed structure with dual metal gate and dual oxide offers significantly improved performance with on-current (ION) of ∼3 orders more than the conventional Double Gate (DG) Tunnel FET and a sub-threshold slope of 31 mV/dec. An ION of 2.7 × 10−5 A/ µm and an OFF current (IOFF) of ∼10−16 A/ µm is achieved in the second proposed device. The AC analysis has revealed that the cutoff frequency (fT) of the second proposed device is 1055 × higher than the conventional DG-TFET. Further, an increase of 3 orders of magnitude is achieved in the gain-bandwidth (GBW) product in the second proposed device in comparison to the conventional DG-TFET.

Study on the Simulation of Biosensors Based on Stacked Source Trench Gate TFET.

In order to detect biomolecules, a biosensor based on a dielectric-modulated stacked source trench gate tunnel field effect transistor (DM-SSTGTFET) is proposed. The stacked source structure can simultaneously make the on-state current higher and the off-state current lower. The trench gate structure will increase the tunneling area and tunneling probability. Technology computer-aided design (TCAD) is used for the sensitivity study of the proposed structured biosensor. The results show that the current sensitivity of the DM-SSTGTFET biosensor can be as high as 108, the threshold voltage sensitivity can reach 0.46 V and the subthreshold swing sensitivity can reach 0.8. As a result of its high sensitivity and low power consumption, the proposed biosensor has highly promising prospects.

Ge‐ and Ge1−zSnz‐Based Gate‐Underlap Dual Material Double Gate Tunnel Field Effect Transistor: Modeling, Optimization, and its Application to Biosensors

Herein, an n‐channel dual material double gate tunnel field effect transistor (DMDG‐TFET) with a gate–drain underlap using Ge and Ge1−zSnz is proposed. An analytical model has been developed to optimize the length of the underlap region for Ge and Ge–Sn alloy as the channel material. The ambipolarity shown by TFET has been utilized to perform a label‐free biosensing in response to the change of permittivity of the biomaterials used in the gate–drain underlap region. The use of Ge–Sn alloy as a channel material results in a lower ambipolar current but higher sensitivity to the presence of biomolecules. DMDG with workfunction (4 and 4.4 eV) is used to optimize the device performance. The analytical results have been validated by the results obtained using commercial software (Silvaco TCAD). A high sensitivity of the biosensor device is obtained by utilizing the tunnel FET ambipolar current with optimized gate underlap of LUD = 55 nm (for Ge) and LUD = 38 nm (for Ge–Sn alloy).

Qualitative Analysis of DG-TFET Structures with Gate Material Engineering

The paper largely focuses on enhancing device parameters of a Double Gate Tunnel Field Effect Transistor structure such as ON current, OFF Current,transconductance and ratio of ON current to OFF current (ION / IOFF) using hetero dielectric gate material. The paper presents three state of art of dual gate TFET i.e., Conventional Double Gate TFET (CDGTFET), horizontally placed Dual Material Double Gate TFET (HDMDGTFET), vertically placed Dual Material Double Gate TFET (VDMDGTFET). The dual material dielectric combinations used in the structures are (SiO2-TiO2), (HfO2-TiO2) and (SiO2-SiC). The Structures are being modeled using Silvaco Atlas tool. Simulations of these structures are carried out and various electrical parameters have been obtained. The results obtained from simulation of these structures are being presented and discussed in this paper. Comparison of the three structures is carried out and resulted in the reduction of ON Current and OFF Current is observed.

Performance Analysis of Reverse T-Shaped Tunnel Field Effect Transistor (RT-DG-TFET) Based Lable–Free Dielectric Modulation Detection of SARS-CoV-2 Virus

In this paper the performance of Reverse T-Shaped Double gate Tunnel field effect transistor is investigated (RT-DG-TFET)with respect to different bio molecules for application as biosensor. The proposed device is built in order to overcome the limitations of short channel effects (SCEs) in MOSFET devices. The recent outbreak due to Corona virus demanded the requirement of a lable free, highly sensitive, quick and meticulous biosensor for the detection of SARS-CoV-2 virus. This device study records the lable free electrical detection of SARS-CoV-2 virus using RT-DG-TFET that detects the virus because of the electrical properties (dielectric constant) of different bio molecules like protein, biotin, air, strepta, APTES, DNA etc. These are studied by using different dielectric modulation techniques in biosensor application. The etched nano-cavity implanted under the gate electrode first immobilizes the SARS-CoV-2 virus, which is subsequently used to identify it. The sensitivity and different analog/RF parameters are also investigated for different bio molecules. All these simulations are investigated in TCAD Sentaurus simulator.