Dielectric Modulation Research Articles

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.

Exploration of Novel Hafnium Oxide (HfO2) Based Plasma-Assisted Gate All Around Carbon Nanotube FET (GAA-CNTFET) for High Sensing Applications

The present research aims to implement a Hafnium Oxide (HfO2) based Plasma-Assisted Gate All Around Carbon Nanotube Field Effect Transistor (GAA-CNTFET) and use it for a better understanding of plasma parameters and their effect on the device. With a more streamlined focus on plasma synthesized (PECVD technique) CNT for channel material, the intention is to understand how the incorporation of high-k dielectrics leads to enhanced device performance. HfO2 is used as a high-k dielectric to overcome the limitations of conventional Silicon Dioxide (SiO2) gate dielectric. A comparative analysis has been performed, based on which it can be concluded that using HfO2 leads to improvement in all observed performance metrics—higher drain current, transconductance, output conductance, early voltage, and gate capacitance. Furthermore, by implementing a cavity in the oxide layer and utilizing the concept of dielectric modulation, it can be observed that tailoring the dielectric permittivity of the cavity affects and alters the device’s performance characteristics. Better performance and high sensitivity are tilted towards a higher dielectric constant value. This analysis’s results help quantify the practical usage of the device for sensing applications in biology, environment and other prominent industries.

Analytical modeling and performance assessment of high performance split-gate dielectric modulated InGaAs GAA junctionless MOSFET biosensor

In this manuscript, split gate dielectric modulated gate-all-around junctionless metal oxide field-effect transistor (SG-GAA-JLFET) based on III-V compound (InGaAs) has recently come forward as a potentiated device in biosensors design due to ultra-sensitivity, selectivity & real-time label-free detection capabilities. In this paper, the boundary conditions at the edges of the junctions are discussed, and their consequences on the Analytical modeling in GAA-JLFET are investigated. The channel-center potential equation is computed by evaluating 2-D Poisson's equation based on the parabolic-potential technique. Additionally, the change of device dimensional parameters upon biosensor sensitivity is computed to investigate the dielectric modulation effects for neutral and charge biomolecules, per se. A SILVACO TCAD simulation tool is utilized for verification and validation of the proposed analytical model. The sensitivity metric of the neutral analyte with a higher dielectric constant is found raised. The value of surface potential sensitivity for Gelatin (k = 12) is seen as 72 which is proportionately 31%, 60%, and 200% greater compared to the sensitivity of apomyoglobin (k = 8), Bacteriophage T7 (k = 6.3), as well as Glucose Oxidase (k = 3.46) for cavity length equal to 20 nm.

Analysis and evaluation of Si(1-x) Ge(x) pocket on sensitivity of a dual-material double-gate dopingless tunnel FET label-free biosensor

This work reports a sensitivity analysis for a dual-material double-gate dopingless Tunnel FET (DM-DG-DLTFET) biosensor carrying a Si(1-x) Ge(x) pocket for improved performance of an overall device. The biomolecules are immobilized in a cavity suitable for small-sized biomolecules detection and the performance of the device is investigated by calculating the electrical properties altered due to the dielectric modulation caused by presence and absence of biomolecules by commercially available ATLASTM tool. The Si(1-x) Ge(x) pocket placed under the cavity at source-channel interface helps to attain better on-current which is usually less in case of other reported structures of Tunnel FETs. The variation in the composition of Ge is observed to obtain enhanced sensitivity. The device is studied for threshold voltage sensitivity of neutral as well as charged biomolecules and the nature of the present biomolecule is also determined using the transconductance-to-current ratio (gm/Ids) which can also be considered as a sensing metric. The optimized device design has been proposed keeping track of the electrical and physical trade-offs. Our results show a maximum of 539.5 mV shift in the threshold voltage when dielectric constant (K) of the neutral biomolecule is varied from 1 to 12 which makes our device evidently an efficient candidate for label-free biosensing application.

A Novel HM-HD-RFET Biosensor for Label-Free Biomolecule Detection.

The mortality of people worldwide caused by COVID-19 has enhanced the research interest to design and develop power-efficient, low-cost, and sensitive biosensors to detect a wide range of biomolecules or foreign particles that can cause severe negative impact on humans. A novel Bio-RFET biosensor with hetero-material (HM) for source/channel and drain regions and hetero-dielectric (HD) is proposed, which acts as an n-MOSFET or a p-MOSFET and n-TFET or p-TFET. This HM-HD-RFET biosensor senses the biomolecules by the label-free dielectric modulation (DM) technique. When the biomolecules are present in the nanocavity, the biosensor can detect the biomolecules without labeling costs. It also changes the dielectric polarization within the nanocavities, and causes a drain current variation in the presence of an electric field. In this research article, (SiO2 + TiO2) and an AlGaAs/Ge-based HD-HM-RFET have been analyzed for their use in biosensing. We found that the proposed device exhibits higher sensitivity as compared to a SiO2 + HfO2-HM-RFET and a Si-based SiO2 + TiO2-RFET for varying dielectric constants (K) from K = 20–80 and charge densities in the range − 5 × 1011 to 1 × 1013 C/cm2. Further, it can be noticed that n-SiO2 + TiO2-HM-TFET possesses the highest Id-Vgs sensitivity of 5.09 × 1013, ION/IOFF ratio of 1.23 × 109, lowest SS of 20.3 mV/dec, and Vth of 1.48 V.

Recent Progress on Sensitivity Analysis of Schottky Field Effect transistor Based Biosensors

In this review, we explored the modern development of schottky field effect transistor (SK FET) structures and the improvement of sensitivity of nanowire sensors using dielectric modulation. Here, the recent developments compared with the conventional schottky FET sensor, and modified conventional configuration have improved sensitivity and faster responses controlled by dielectric modulation and changing the barrier height. The change in sensitivity- with the current optimization has been considered for dissimilar gate, and drain voltage. The dielectric modulation can advance the finding limits, sensitivity, and reaction time of the novel structures in dissimilar applications, such as U-V finding, gas and chemical/ biosensing. In addition, the efficiency and doped channel have been deliberately studied under dissimilar biomolecule model specifications. This article reviews a recent study on emerging future generation SK FET biosensors with their sensitivity performance and the effect of their metal and channel contact is presented.

Langevin dynamics/Monte Carlo simulations method for calculating nanoscale dielectric functions of materials

We have developed a simulational methodology for calculating the nanoscale frequency-dependent complex dielectric function of a wide range of materials using a combination of Langevin dynamics and Metropolis Monte Carlo methods. The premise of such a scheme is to use the atomistic structure of materials and designate appropriate interatomic interactions as well as internal field couplings to accommodate correlated materials. We validate our model by recreating the dielectric functions of well-studied representative materials including insulator ${\text{SiO}}_{2}$ thin film that has phonon resonances in the midinfrared, and semiconductor monolayer ${\text{MoS}}_{2}$ that exhibits strong excitonic resonances in the visible frequency range. To further showcase the capability of the model in calculating nanoscale dielectric modulation of complex materials, we simulate the dielectric response of ${\text{SmNiO}}_{3}$, a correlated perovskite oxide, with respect to differing levels of hydrogenation, oxygen vacancy formation, and external fields. This is accomplished by inserting and tracking the movement of dopants at the nanoscale using Metropolis Monte Carlo methods that explicitly include interactions with each other as well as external fields. Simulated nanoscale dielectric spectra agree very well with high-resolution near-field experimental measurements based on scattering type scanning near-field microscopy. We find that this modeling scheme carries a broad utility in describing and predicting the nanoscale dielectric behavior of a broad range of materials exposed to changing local environments.

Impact of biomolecules position and filling area on the sensitivity of hetero stack gate MOSFET

A two-dimensional dual material double hetero stack gate (DMDG-HSG-MOSFET) based biosensor is proposed for the identification of label-free biomolecules like uricase (K = 1.54), streptavidin (K = 2.10), ferrocytochrome C(K = 4.7), and protein (K = 8). The influence of the biomolecule's position and filling area (100%, 66.66%, and 33.33%) has been inspected to detect the device sensitivity. The electrical parameters like device current, threshold voltage, current sensitivity, voltage sensitivity, and subthreshold performance of the device are examined by considering the neutral biomolecules. Further, the device performance optimization has been done by varying the oxide thickness (tox) using the dielectric modulation method. The performance parameters are analyzed for the biomolecules filling areas 100%, 66.66% and 33.33% and the analysis provides better results with protein biomolecule. For protein biomolecule with a 100% filling area the threshold voltage, current, and subthreshold swing sensitivities are obtained as 0.69, 1.96, and 1.09 respectively.

Silicon Dielectric Diplexer Module for 600-GHz-Band Frequency-Division Multiplexing Wireless Communication

We developed a silicon (Si) dielectric diplexer module for 600-GHz-band frequency-division multiplexing wireless communication. This diplexer was developed based on Si dielectric waveguide technology, which provides low-loss transmission characteristics compared with the conventional metallic terahertz-transmission platform, such as metallic hollow waveguides. It includes straight waveguides based on an effective medium composed of Si and air, and a coupler comprising of two adjacent unclad Si waveguides. Furthermore, for the communication system integration, we developed a practical and low-insertion loss module with WR1.5 metallic hollow waveguide input–output interfaces and modularized the diplexer. We performed transmission measurement experiments with the fabricated diplexer module and achieved 3-dB bandwidths of 101 and 37 GHz, and crosstalk of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> 34 dB at 680 GHz and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> 41 dB at 618 GHz in the cross and bar directions, respectively. Finally, we performed a two-channel wireless communication experiment using the developed diplexer module in the 600-GHz band. We achieved error-free communication at 10 and 6 Gbit/s on the cross and bar channels, respectively. In addition, we achieved a data rate of up to 12.5 Gbit/s at the forward error correction limits for both channels.

Design of Ultracompact High‐Speed‐Integrated Lithium–Niobate Periodic Dielectric Waveguide Modulator

Modern communications and microwave photonics require compact electro‐optic modulators with ultrahigh bandwidth and low power consumption. These requirements can be satisfied by integrated lithium–niobate electro‐optic modulators with high bandwidth and low power consumption. However, most integrated lithium–niobate modulators cannot achieve a good balance between an ultracompact size and a high modulation bandwidth. These challenges are overcome by designing an integrated lithium–niobate periodic dielectric waveguide modulator, featuring a compact modulation length of 87.4 μm, a theoretical modulation bandwidth over 600 GHz, a voltage‐length product of 0.0874 V cm, and a high sideband suppression ratio up to 36.1 dB. These performances are achieved by taking advantage of a capacitor configuration consisting of a nonresonant periodic dielectric waveguides sandwiched between two indium tin oxide (ITO) electrodes. This design provides an ultrabroadband and compact solution to next‐generation communications and microwave photonics.

Analytical modelling for surface potential of dual material gate overlapped-on-drain TFET(DM-DMG-TFET) for label-free biosensing application

This article presented the first-ever 2D analytical model for the surface potential of dual material gate overlapped-on-drain TFET (DMG-TFET) device for label-free biosensor application using dielectric modulation technique. The use of two different metal work functions for the gate (ϕM1<ϕM2) impacts the device’s surface potential to increase tunneling width at the secondary tunneling junction to enhance the device sensitivity compared to single material gate device. This model takes into account the effect of changing the dielectric constant value, location, and percentage of fill factor of the target biomolecules on the surface potential of the device. The parabolic approximation of surface potential is used for solving the 2D-Poisson’s equation by applying suitable boundary conditions. The analytical surface potential results are verified with the simulation result using the SILVACO Atlas tool.

Analytical Exploration and Simulation of Dual-Material Gate Macaroni Channel MOSFET biosensor using dielectric-modulation technique

The paper presents extensive analytical modeling and simulation of a novel Dual-Material Gate Macaroni-Channel MOSFET to act as a biosensor for detection of neutral as well as charged biomolecules using dielectric modulation approach. Dielectric modulation in a MOSFET device is the alteration in the dielectric constant in the gate dielectric region of the device. Presence of biomolecules (in a nanogap etched under the gate of the projected device) having different dielectric constants impact the gate capacitance that in turn affects the device features such as potential, threshold voltage, drain current which undergo considerable shift in presence of biomolecules. Detailed Sensitivity analysis based on threshold voltage shift for different types of biomolecule allows suitable detection of biomolecule type. Suitable selection of device outer radius allows significant suppression of some major Short channel effects such as threshold voltage reduction, reduced subthreshold swing enabling superior device performance. Finally, comparative sensitivity analysis of the proposed device with its full channel Cylindrical Gate-all-around counterpart having same channel thickness exhibits better sensitivity capability of the proposed device for both neutral and charged biomolecule. Analytical results are substantiated using Atlas simulation outputs.

Recent Study on Schottky Tunnel Field Effect Transistor for Biosensing Applications

In this review, we discussed highly sensitive biosensor devices which is having a more attractive, wide scope and development in the sensing field. Biosensor devices can detect the charged and neutral charged biomolecules such as protein, nucleic acids, antibody agents and viruses. Due to these highly sensitive biosensor devices, we mainly focused on schottky tunnel field-effect transistors (STFET), these transistors have unique properties such as enhanced transconductance and gate controllability, low leakage current etc. In addition, we studied the performances and challenges of STFET by dielectric modulation doping concentration, dielectric modulation, and heterostructure devices. Further, we have reviewed the comparison of STFET and conventional devices. This article reviews mainly on the study of high sensitivity analysis of STFET and modified Schottky-TFET structures for the use of biosensing applications.

Ge/GaAs Based Negative Capacitance Tunnel FET Biosensor: Proposal and Sensitivity Analysis

A highly sensitive, accurate, fast and power efficient biosensor is the need of the hour. Undoubtedly, dielectrically modulated (DM) tunnel FET (TFET) assures better sensitivity as compared to MOSFET biosensors in case of label-free biosensing. However, there exists immense possibilities to upgrade TFET biosensor properties through the improvement of its DC characteristics. Therefore, in this paper a ferroelectric (FE) gate oxide and a hetero material (HM) source/drain-channel based TFET is designed for biosensor applications. A FE layer of HfZrO2 above SiO2 gives rise to negative capacitance (NC) effect that causes voltage amplification and hence, boosts subthreshold swing (SS) and ION/IOFF ratio. In addition, use of a low band gap material (Ge) in source and a high band gap material (GaAs) in drain-channel junctions enhances the probability of band-to-band-tunneling (BTBT) of charge carriers. Further, to introduce biomolecules, a cavity is impinged below HfZrO2 near SiO2 above source/channel junction that modulates BTBT as a function of charge density (Nf) and dielectric constant (K). This paper presents a detailed comparative analysis of Ge/GaAs-NCTFET and Ge/GaAs-TFET biosensors for different K and Nf values from which we can conclude that the incorporation of NC effect in TFET biosensors leads to enhanced sensitivity with high speed and low power consumption.

Analytical modeling of dielectrically modulated broken-gate tunnel FET biosensor considering partial hybridization effect

Currently Tunnel Field Effect Transistors (TFET) have picked up tremendous recognition in bio-sensing applications. Having a similar perspective, this paper proposes a preliminary novel channel centre potential based analytical model for broken gate TFET biosensor device. The model incorporates dielectric modulation and steric hindrance effects and demonstrates the effect of device parameter variations and partial hybridization in the nano-cavity on the sensitivity of the bio-sensor. Two types of fill profiles have been examined for sensitivity variation. The model shows good agreement with the real time TCAD simulation data and existing literature. Also, the model proves its robustness by responding in conditions of low channel occupancy (∼40%) and for biomolecules ranging from medical to industrial grade (high-K). The model is computationally intuitive and provides scope for application specific optimizations. The broken structure helps in reducing the ambipolarity without adversely affecting the sensitivity of the biosensor.

Analytical Modeling of MgZnO/ZnO MOSHEMT Based Biosensor for Biomolecule Detection

In recent development, the High Electron Mobility Transistor (HEMT) technology was used for biosensor applications. In this contribution, an analytical model of MgZnO/ZnO MOSHEMT (Metal Oxide Semiconductor HEMT) was reported. For the first time, a nanogap cavity-based biosensor aimed at detecting various biomolecules, such as uricase, streptavidin, ChOx, and proteins, was designed. The developed analytical model was used to calculate the two-dimensional electron gas (2DEG) density, device capacitance, drain current (ID), output conductance (gd), and transconductance (gm) by using the dielectric modulation approach. MOSHEMTs used dielectric modulation, with the nanogap cavity considered under the gate region. The effective capacitance in the cavity region was obtained by using dielectric modulation. Hence, the nanogap cavity acts as a sensing area for the immobilisation of target biomolecules. The sensitivity of the device was analysed by observing the strong changes in drain current with the addition of different biomolecules in the nanogap cavity region. The proposed MgZnO/ZnO MOSHEMT biosensor exhibits a quick response to biomolecule changes since its drain-on-sensitivity (SIon) is comparatively higher than that of other semiconductor-based biosensors. The obtained analytical model results were verified by a comparison with other works available in the literature, and they showed good agreement with our results.

Power and delay analysis of dielectric modulated dual cavity Junctionless double gate field effect transistor based label-free biosensor

Recently, Metal Oxide Semiconductor Field Effect Transistor (MOSFET) based biosensors have gained immense attraction as a diagnostic tool for point-of-care testing. This paper investigates the current sensitivity, power consumption, and intrinsic delay of the Dual Cavity Junction-less (JL) Double gate MOSFET-based biosensor. Dielectric modulation has been incorporated for label-free biosensing. The impact of neutral and charged biomolecules has been investigated on the current sensitivity, power consumption, and delay. Extensive simulation using SILVACO ATLAS has been done to study the effects. Efficacy of the dual cavity in comparison to the single cavity in JL-MOSFET is demonstrated in terms of better current sensitivity and less power consumption. This work demonstrates the low-power JL-MOSFET-based label-free biosensors for the implementation of cost-efficient and simpler analytical tools for the screening of drugs and biomolecules.

Performance Analysis of MOS-HEMT as a Biosensor: A Dielectric Modulation Approach

A dielectric modulated MOS-HEMT is investigated for different neutral and charged biomolecules with cavities embedded on the source side. To analyze the performance of the device, neutral and charged biomolecules are immobilized in the cavity independently. The neutral biomolecules are emulated by dielectric constant in the cavity and the charged biomolecules are emulated by varying interface charge at oxide/AlGaN interface. The proposed structure is simulated using the ATLAS Silvaco device simulation tool. The sensitivity of the device is optimized by various parameters such as barrier mole fraction and cavity length. The performance of the device is evaluated by the change in drain current and shift in threshold voltage. It has been observed that the drain current and threshold voltage varies with dielectric modulation of the cavity and change in biomolecular charge. The effect of neutral and charged biomolecules is also analyzed for channel potential and channel conductance. As observed from the results, the variation in $$\mathrm {g}_{\mathrm {d}}$$ due to neutral biomolecules is very high as compared to charged biomolecules. It shows very less variation in $$\mathrm {g}_{\mathrm {d}}$$ for charged ranges from $$3\times 10^{12}/\mathrm {cm}^2$$ to $$-5\times 10^{11}/\mathrm {cm}^2$$ .

A Novel RFET Sensor for Label-Free Biomolecule Detection

In the current scenario, COVID-19 has created a havoc negative impact on the lives of the people, which have triggered the research interest on the design and development of sensitive, low cost and power-efficient sensors for detecting a wide variety of biomolecules. Here, a novel hetero dielectric (HD) hetero material (HM) Bio-RFET based sensor is proposed which works as n or p MOSFET and n or p TFET and hence, is capable to sense the biomolecules through label-free dielectric modulation technique. Without labelling expenses, this biosensor detects a number of biomolecules present in human body as and when kept in a nano cavity. The dielectric polarization within the nanocavity due to the presence of foreign biomolecules under the influence of an electric field causes a variation in drain current. In this paper (SiO2 + TiO2) and AlGaAs/Si based HD-HM-RFET is explored for biosensing applications and mole fraction optimization of AlGaAs is done to obtain better results for four FETs. Work function of 4.5 eV is used in over drain and source electrodes, while metal work function of 4.7 eV is used for gate electrode. Finally, we found that the proposed device possesses better sensing capability for varying dielectric constant (K = 20 to 80) and charge (−5 × 1011 to 1 × 1013 C/cm2) as compared to a (SiO2 + HfO2)-HM-RFET and Si based (SiO2 + TiO2)-RFET. Further, it is observed that n-(SiO2 + TiO2)-HM-TFET is the best among all FETs and has highest Id-Vgs sensitivity = 5.09 × 1013, ION/IOFF = 1.23 × 109, lowest SS = 20.3 mV/dec and Vth = 1.48 V.

Analytical Modeling of Sensitivity Parameters Influenced by Practically Feasible Arrangement of Bio-Molecules in Dielectric Modulated FET Biosensor

In this paper, analytical modeling of a Dielectric Modulated Double Gate Field Effect Transistor (DM-DGFET) for biosensing application is presented with extensive data analysis. Firstly, the size of the nanogaps and arrangements of biomolecules in those gaps are optimized with respect to the sensitivity of the above sensor. The optimized DM-DGFET is next analyzed on the basis of its modeling and simulation. This paper addresses novel issues arising from arrangements of biomolecules, especially from practical point of view. Effect of probe placement due to steric hindrance and random nature of biomolecules, are also considered. The capacitances associated with the nanogaps occupied by biomolecules, following various arrangements, are modeled. Expressions of the threshold voltage, drain current and its sensitivity in terms of variations are also derived using the capacitance model. A comparative study of the proposed and the existing architectures is made. The influence of process variation on the sensitivity of the sensor is also studied. The results from the proposed analytical model are validated with the simulated data obtained from TCAD device simulator. In conclusion, the proposed DM-DGFET based biosensor architecture will emerge as an optimal model, very useful for the study on this field in future.