Modulated Tunnel Field Effect Transistor Research Articles

A novel TFET based nanogap high-sensitive biosensor by boosted reliability- new metric for sensitivity definition

This is a detailed report about the proposal of an efficient nanogap dielectrically modulated tunnel field-effect transistor (TFET) biodevice granting a high sensitivity in the detection of the targeted biomolecules while keeping high performance in the realistic situations with boosting the reliability. Two attractive approaches in the cases of the bandgap engineering and charge plasma concept have been suggested for the band energy correction increasing the sensing current and the sensitivity without occurrence possibility of fabrication process related issues as compared to common TFET and PNPN TFET biosensors. The streptavidin, biotin and APTES samples have been selected as typical biomolecules for the sensing performance comparison of the biosensors under the study. Also, the proposed biosensor showed performance superiority for other biomolecules. For the first time, a new metric for measuring sensitivity is proposed to combine both maximum current sensitivity and well-defined average sensitivity in a unique relation named effective sensitivity. This prevents the possible noise impact on the sensitivity of the biosensors since the TFET based biosensors suffer from the low detection current. Defining the effective sensitivity, the proposed biosensor has been evaluated in more realistic conditions including partial hybridization of biomolecules inside the nanogap, trap-assisted-tunneling (TAT) component, neutral/charged biomolecules and biomolecules accumulation in different orientations showing the performance superiority of the proposed biosensor.

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.

Performance Analysis of the Diagonal Tunneling-Based Dielectrically Modulated Tunnel FET for Bio-Sensing Applications

In this work, a Diagonal Tunneling Dielectrically Modulated Tunnel Field Effect Transistor (DT-DMTFET) architecture is proposed for label-free bio-sensing application. The performance of this sensor architecture is comprehensively investigated with the help of extensive numerical device simulations. The architecture has been carefully engineered to exploits the diagonal band to band tunneling (BTBT) component in favor of bio-molecule detection. The essential physics of the transduction mechanism for lateral tunneling, vertical tunneling, and diagonal tunneling-based DMTFETs is extensively analyzed from device electrostatics and transport mechanisms. The transduction efficiency of the sensor devices is quantitatively assessed in terms of current sensitivity, where DT-DMTFET exhibits a sensitivity of 3590 compared to 2514 and 1550 observed in lateral tunneling (LT) and vertical tunneling (VT) dominated DMTFETs, respectively. The optimum sensitivity of DT-DMTFET is observed at 4V and 0.4 V gate and drain biases ranges of operation, where the same is observed at a gate bias of 5V and 7V for LT- and VT- DMTFET, respectively. Furthermore, the device design aspects are studied in detail to identify the relevant structural parameters and subsequently optimize the sensing performance of the DT-DMTFET. Finally, an extensive comparative performance study establishes that the DT-DMTFETs offer more than 50% and 100 % improvements in the current sensitivity compared to their lateral and vertical tunneling-based counterparts, respectively, over a range of bio-molecule sample specifications.

Performance analysis of double-metal-gate dual-cavity dielectrically modulated-TFET as a label free biosensor

In this paper, a double metal gate dual cavity dielectrically modulated tunnel field effect transistor (DMG-DC-DMTFET) biosensor is proposed. The On and ambipolar currents of the device are used for detection of various biomolecules. The cavities, where biomolecules get immobilized are considered at both source-channel and drain-channel junctions of TFET in order to utilize ambipolar nature of TFET to detect the presence of biomolecules in an efficient way. Sensitivity improvement and reduction in Off current at higher dielectric constant of biomolecules are done by considering the gate metal work function engineering. The effect of charged and neutral biomolecules on band energy, transfer characteristics and electric field has been analyzed.

Investigation on the Effects of Substrate, Back-Gate Bias and Front-Gate Engineering on the Performance of DMTFET-Based Biosensors

In this work, the performance of a Double-Gated Silicon on Insulator (DG-SOI) Dielectrically Modulated Tunnel Field Effect Transistor (DMTFET) architecture is systematically investigated for label-free bio-sensing applications with the help of extensive device-level simulations. In this context, the effects of bulk oxide (BOX) substrate and back-gate biasing are emphasized and analyzed from the cavity and channel electrostatics and Band to Band Tunneling (BTBT) component of DMTFET. It is found that the electrostatic coupling between BOX substrate and channel significantly degrades the sensing performance of DG-SOI DMTFETs, whereas an applied negative back-gate bias enhances the performance of such transducer. In this line, a dual metal (DM) gate architecture is introduced that can effectively enhance the influence of applied back-gate bias and thereby leads to sensitivity improvement from 10% to 110% in DM DG-SOI DMTFET depending on bio-molecule sample specifications. Furthermore, it is observed that for suitable applied back-gate bias, the interface trap-state induced variations in sensitivity of DG-SOI DMTFETs can be reduced by even an order of magnitude. Finally, a comparative sensing performance study of proposed DMTFET with their reported counterparts establishes the advantage of such biosensors for bio-molecules with smaller dielectric constant. A similar study also shows the superiority of the proposed DMTFET over its MOSFET counterpart for wide bio-molecular sample specifications.

Performance analysis of gate engineered dielectrically modulated TFET biosensors

ABSTRACT This paper presents, a short gate dual metal source electrode dielectrically modulated tunnel field-effect transistor (SDM SE DM-TFET) has been compared with conventional dual gate-source electrode dielectrically modulated tunnel field-effect transistor (DG SE DM-TFET) for the biosensing application. Hence, gate work function engineering is applied in our proposed device in which gate metal is split into two different work function segments as and . Additionally, a potential of −1.2 V is applied to the source electrode having a work function of . is the gate electrode work function at the source side and is the gate electrode work function at the drain side. The investigation is performed by varying the dielectric constant and charge density for choosing an optimised value for . The performance comparison has been done in terms of current, sensitivity and sensing speed. It can be verified from the simulated results that our proposed device exhibits superior performance as compared to the existing structures.

Performance Assessment of A Novel Vertical Dielectrically Modulated TFET-Based Biosensor

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 ( $\rho $ ), ${x}$ -composition of Ge, % volume filling of ${t}_{\textsf {cavity}}$ , 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.