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 ∼109 for 3-aminopropyltriethoxysilane (APTES) biomolecule, and Selectivity of ∼102 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. © 2020 IOP Publishing Ltd.

Rohit Singh

Electrical Engineering

(SoE) School of Engineering

Dwivedi P.

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Shiv Nadar University

Engineering Research Express

In this work, a new simulation approach of transient analysis on single cavity dielectric-modulated (DM) p-type of tunnel field-effect transistor (TFET) is examined for biosensing applications. The device operation and performance are investigated using the 2D device simulator and results are well-calibrated with experimental data. In this work, we have examined DC transfer characteristics, the transient response of drain current, drain current sensitivity (S), and selectivity (Δ S). Focussing more on the transient results, we have obtained maximum sensitivity of orders greater than 108 for APTES biomolecule with respect to air and a significant selectivity value in orders of 103 for APTES with respect to Biotin biomolecule. The performance of the device in terms of selectivity can be further improved (104) by optimizing the back-gate bias, and therefore, the impact of back-gate bias has been analysed. The results for charged biomolecules and partially filled cavity are further investigated highlighted. The DM p-TFET biosensor shows a significant improvement in the results with the transient response for biosensing applications with the feasibility of operating at low voltages (gate voltage of-2.0 V, drain voltage of-0.5 V and back gate voltage 0 to 0.5 V). © 2001-2012 IEEE.

IEEE Sensors Journal

A New Simulation Approach of Transient Response to Enhance the Selectivity and Sensitivity in Tunneling Field Effect Transistor-Based Biosensor

In this work, an underlap structure of tunneling field-effect transistor (TFET) containing electrolyte/watery solution is examined to enhance the Nernst limit (59 mV/pH) of sensitivity. After incorporating the electrolyte medium in TFET, effect of pH variation on device characteristics such as drain current vs front gate voltage, voltage sensitivity, and current sensitivity are investigated. The interface charge density at the oxide-silicon interface of TFET is obtained as a function of electrolyte pH from physics-based modelling. Voltage sensitivity value 180 mV/pH that is greater than three times of Nernst limit of 59 mV/pH and current sensitivity value that is more than one decade per pH are observed for TFET based sensor. In order to validate the results, models used in TFET are well-calibrated with experimental data and the result of TFET are compared with inversion mode (IM) device. Results show that TFET gives superior performance than IM device; hence an underlap TFET can be a promising alternative for the next generation biosensor. © 2001-2012 IEEE.

Crossing the Nernst Limit (59 mV/pH) of Sensitivity through Tunneling Transistor-Based Biosensor

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

Overcoming Biomolecule Location-Dependent Sensitivity Degradation Through Point and Line Tunneling in Dielectric Modulated Biosensors

Dielectric Modulated Biosensor Architecture: Tunneling or Accumulation Based Transistor?

IEEE Transactions on Electron Devices

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

Applicability of Transconductance-to-Current Ratio ( $g_{mathrm {m}}/I_{mathrm {ds}}$ ) as a Sensing Metric for Tunnel FET Biosensors

Investigation the impact of the gate work-function and biases on the sensing metrics of TFET based biosensors