Investigation and Design of Dual Gate Dielectrically Modulated Junction less TFET for Biomolecule Recognition (original) (raw)
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Dielectric Modulated Tunnel Field-Effect Transistor—A Biomolecule Sensor
IEEE Electron Device Letters, 2012
In this letter, we propose a dielectric modulated double-gate tunnel field-effect transistor (DG-TFET)-based sensor for low power consumption label-free biomolecule detection applications. A nanogap-embedded FET-based biosensor has already been demonstrated experimentally, but a TFET-based biosensor has not been demonstrated earlier. Thus, a concept of TFET-based sensor is presented by analytical and simulation-based study. The results indicate better sensitivity toward two different effects (dielectric constant and charge of biomolecule) in comparison with a FET-based biosensor, and the additional advantages of CMOS compatibility, low leakage (low static power dissipation), and steep subthreshold slope make TFET an attractive alternative architecture for CMOS-based sensor applications.
IEEE Transactions on Electron Devices, 2012
In this paper, an analytical model for a p-n-p-n tunnel field-effect transistor (TFET) working as a biosensor for label-free biomolecule detection purposes is developed and verified with device simulation results. The model provides a generalized solution for the device electrostatics and electrical characteristics of the p-n-p-n-TFET-based sensor and also incorporates the two important properties possessed by a biomolecule, i.e., its dielectric constant and charge. Furthermore, the sensitivity of the TFET-based biosensor has been compared with that of a conventional FET-based counterpart in terms of threshold voltage (V th) shift, variation in the ON-current (I on) level, and I on /I off ratio. It has been shown that the TFET-based sensor shows a large deviation in the current level, and thus, change in I on can also be considered as a suitable sensing parameter. Moreover, the impacts of device parameters (channel thickness and cavity length), process variability, and process-induced damage on the sensitivity of the biosensor have also been discussed.
IEEE Transactions on Electron Devices, 2015
In this paper, a short-gate tunneling-field-effecttransistor (SG-TFET) structure has been investigated for the dielectrically modulated biosensing applications in comparison with a full-gate tunneling-field-effect-transistor structure of similar dimensions. This paper explores the underlying physics of these architectures and estimates their comparative sensing performance. The sensing performance has been evaluated for both the charged and charge-neutral biomolecules using extensive device-level simulation, and the effects of the biomolecule dielectric constant and charge density are also studied. In SG-TFET architecture, the reduction of the gate length enhances its drain control over the band-to-band tunneling process and this has been exploited for the detection, resulting to superior drain current sensitivity for biomolecule conjugation. The gate and drain biasing conditions show dominant impact on the sensitivity enhancement in the short-gate biosensors. Therefore, the gate and drain bias are identified as the effective design parameters for the efficiency optimization. Index Terms-Band-to-band tunneling (BTBT), biosensors, dielectric modulated tunneling-field-effect transistor (DMTFET), tunnel field-effect transistor (FET).
Chapter 2 Dielectric-Modulated TFETs as Label-Free Biosensors
2018
This chapter presents tunnel field effect transistors (TFETs) as dielectric-modulated (DM) label-free biosensors, and discusses various aspects related to them. A brief survey of the dielectric-modulated TFET biosensors is presented. The concept of dielectric modulation in TFETs is discussed with focus on principle and design perspectives. A Technology Computer Aided Design (TCAD) based approach to incorporate embedded nanogaps in TFET geometries along with appropriate physics-based simulation models are mentioned. Non-ideal conditions in dielectric-modulated biosensors are brought to light, keeping in view the practical considerations of the devices. A gate engineered TFET is taken up for analysis of sensitivities under different conditions through TCAD simulations. Finally, a status map of the sensitivities of the most significant works in dielectric-modulated label-free biosensors is depicted, and the status of the proposed TFET is highlighted.
Performance Assessment of A Novel Vertical Dielectrically Modulated TFET-Based Biosensor
IEEE Transactions on Electron Devices, 2017
A vertical dielectrically modulated tunnel field-effect transistor (V-DMTFET) as a label-free biosensor has been investigated in this paper for the first time and compared with lateral DMTFET (L-DMTFET) using underlap concept and gate work function engineering. To improve the performance of lateral biosensor (LB), a heavily doped front gate n +-pocket and gate-to-source overlap is introduced in the vertical biosensor (VB). The integrated effect of lateral tunneling as well as vertical tunneling in VB leads to enhanced ON-state current and decrease the subthreshold swing. To evaluate sensing ability of these devices, charged and charged neutral biomolecules are immobilized in nanogap cavity independently. A deep analysis has been performed to show the effect of variation in dielectric constant (k), charge density (ρ), x-composition of Ge, % volume filling of t cavity , length and thickness of a n +-pocket and sensitivity of electrical parameters is also incorporated. Dual-pocket (front and back gate pocket) VB is studied and compared with the LB and VB in the tabular form. Noise characteristic of dielectrically modulated field-effect transistor, L-DMTFET, and V-DMTFET is also evaluated. Index Terms-Band-to-band tunneling (BTBT), dielectrically modulated tunnel field-effect transistor (DMTFET), lateral biosensor (LB), n +-pocket, overlap gate, vertical biosensor (VB). I. INTRODUCTION T HE field-effect transistor (FET)-based biosensors are very popular for label-free detection process and also compatible for the CMOS technology [1]-[4]. FET-based biosensors have some critical challenges such as high subthreshold swing (SS > 60 mV/decade) due to kT/q limit and large response time. This can be eradicated by tunnel FET (TFET)based biosensor as TFET possesses SS <60 mV/decade due to its band-to-band-tunneling (BTBT) mechanism [5]-[7]. Along with this, response time (time required to detect the target biomolecules in the cavity) for TFET-based biosensor is lower because of its lower SS [6]. On this basis, TFET-based Manuscript
Dielectric-Modulated TFETs as Label-Free Biosensors
Design, Simulation and Construction of Field Effect Transistors, 2018
This chapter presents tunnel field effect transistors (TFETs) as dielectric-modulated (DM) label-free biosensors, and discusses various aspects related to them. A brief survey of the dielectric-modulated TFET biosensors is presented. The concept of dielectric modulation in TFETs is discussed with focus on principle and design perspectives. A Technology Computer Aided Design (TCAD) based approach to incorporate embedded nanogaps in TFET geometries along with appropriate physics-based simulation models are mentioned. Non-ideal conditions in dielectric-modulated biosensors are brought to light, keeping in view the practical considerations of the devices. A gate engineered TFET is taken up for analysis of sensitivities under different conditions through TCAD simulations. Finally, a status map of the sensitivities of the most significant works in dielectric-modulated label-free biosensors is depicted, and the status of the proposed TFET is highlighted.
Journal of Electronic Materials, 2018
Nanoscale devices are emerging as a platform for detecting biomolecules. Various issues were observed during the fabrication process such as random dopant fluctuation and thermal budget. To reduce these issues charge-plasmabased concept is introduced. This paper proposes the implementation of charge-plasma-based gate underlap dielectric modulated junctionless tunnel field effect transistor (DM-JLTFET) for the revelation of biomolecule immobilized in the open cavity gate channel region. In this p+ source and n+ drain regions are introduced by employing different work function over the intrinsic silicon. Also dual material gate architecture is implemented to reduce short channel effect without abandoning any other device characteristic. The sensitivity of biosensor is studied for both the neutral and charge-neutral biomolecules. The effect of device parameters such as channel thickness, cavity length and cavity thickness on drain current have been analyzed through simulations. This paper investigates the performance of charge-plasma-based gate underlap DM-JLTFET for biomolecule sensing applications while varying dielectric constant, charge density at different biasing conditions.
Modeling and Simulation of a TFET-Based Label-Free Biosensor with Enhanced Sensitivity
Chemosensors
This study discusses the use of a triple material gate (TMG) junctionless tunnel field-effect transistor (JLTFET) as a biosensor to identify different protein molecules. Among the plethora of existing types of biosensors, FET/TFET-based devices are fully compatible with conventional integrated circuits. JLTFETs are preferred over TFETs and JLFETs because of their ease of fabrication and superior biosensing performance. Biomolecules are trapped by cavities etched across the gates. An analytical mathematical model of a TMG asymmetrical hetero-dielectric JLTFET biosensor is derived here for the first time. The TCAD simulator is used to examine the performance of a dielectrically modulated label-free biosensor. The voltage and current sensitivity of the device and the effects of the cavity size, bioanalyte electric charge, fill factor, and location on the performance of the biosensor are also investigated. The relative current sensitivity of the biosensor is found to be about 1013. Besi...
Silicon, 2020
In this work, the performance of a Si 0.5 Ge 0.5 sourced dual electrode doping-less Tunnel FET (DEDLTFET) biosensor using dielectric modulation is studied for different cavity length, thickness (T bio) and charge densities (QF). The use of silicongermanium (SiGe) based source also shows an improvement in the performance of the charge plasma Tunnel FET because of its enhanced drain current. Biomolecules are introduced inside the cavity region and their impact on the drain current has been investigated to design the biosensor. The sensitivity factor of the biosensor depends upon the drain current obtained which is proportional to the dielectric constant (k) and the charge density of the biomolecules. The proposed biosensor achieves a maximum drain current sensitivity of 7.7 × 10 8 at a cavity length of 25 nm and 2.7 × 10 9 at a cavity length of 30 nm. When compared with the conventional TFET biosensors, it is observed that Si 0.5 Ge 0.5 sourced doping-less TFET biosensor provides better drain current sensitivity.
Engineering Research Express, 2020
In this work, we examined the impact of gate work-function and back-gate bias to enhance sensing metrics of a Dielectric Modulated (DM) p-type Tunnel Field Effect Transistor (p-TFET) based biosensor. The sensing metrics, namely Sensitivity (S) and Selectivity (ΔS) are considerably improved by using a lower value of gate work-function and positive back gate voltages. It is shown that by appropriate selection of gate work-function and back gate bias, Band-to-Band Tunneling (BTBT) of carriers is reduced and a significant change in electrical characteristics is observed in a device with an empty cavity. Therefore, the relative change in the drain current due to the presence of biomolecules in the nanogap cavity is maximized. Results indicate a Sensitivity of ∼10 9 for 3-aminopropyltriethoxysilane (APTES) biomolecule, and Selectivity of ∼10 2 for APTES concerning Biotin biomolecule in an optimally designed p-TFET biosensor. The impact of location, as well as the charge of biomolecules, are also analyzed in this work. Results showcase the additional degree of freedom through device optimization which facilitates the tunability of sensing metrics for improved biosensor performance.