Exploring p-channel TFET for Optimum Cavity-Length Window in Detecting a Wide Variety of Protein-Molecules with the Effect of Their Position Dependent Variability on Sensitivity
TL;DR: In this paper, the performance of a sub-100nm gate-length p-channel TFET-based biosensor (pTFET-BS) covering a wide range of protein-molecules is presented.
Abstract: The performance of a sub-100-nm gate-length p-channel TFET-based biosensor (pTFET-BS) covering a wide range of protein-molecules is presented, and for the first time the optimized length-range of t...
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TL;DR: In this paper , an electrically doped cavity on source junctionless tunnel field effect transistor (ED-CS-JLTFET)-based biosensor is proposed for label-free detection of biomolecules.
Abstract: The tunnel field-effect transistor (TFET) has emerged as a promising device for biosensing applications due to band-to-band tunneling (BTBT) operation mechanism and a steep subthreshold swing. In this paper, an electrically doped cavity on source junctionless tunnel field-effect transistor (ED-CS-JLTFET)-based biosensor is proposed for label-free detection of biomolecules. In the proposed model, the electrically doped concept is enabled to reduce fabrication complexity and cost. In order to create a nano-cavity at the source region, some portion of the dielectric oxide of the polarity gate terminal is etched away. To perceive the presence of biomolecules, two important properties of biomolecules, such as dielectric constant and charge density, are incorporated throughout the simulation. The sensing performance of the proposed ED-CS-JLTFET-based biosensor has been analyzed in terms of transfer characteristics, threshold voltage and subthreshold swing. In addition, the sensitivity of the proposed biosensor has also been analyzed with respect to different fill factors (FFs), varying nano-cavity dimension and work-function of the control gate. It is found from the simulated results that the proposed ED-CS-JLTFET-based biosensor offers higher current sensitivities with neutral, positively charged and negatively charged biomolecules of [Formula: see text] (at k [Formula: see text]), [Formula: see text] (at [Formula: see text] and [Formula: see text] C[Formula: see text]cm[Formula: see text]) and [Formula: see text] (at k [Formula: see text] and [Formula: see text] C[Formula: see text]cm[Formula: see text]), respectively.
2 citations
TL;DR: In this article, a unique pTFET-based biosensor device having channel epilayer has been introduced and its performance in the sensing domain has been studied in terms of five different sensitivity parameters.
Abstract: In this paper, for the first time, a unique pTFET-based biosensor device having channel epilayer has been introduced and its performance in the sensing domain has been studied in terms of five different sensitivity parameters. A rigorous analysis of the effect of the existent corner point (corner-effect) in the proposed device architecture on the sensitivity metrics has been performed for five different channel epilayer thicknesses, covering five different types of protein-molecules, viz., Apomyoglobin, Myoglobin, Protein-G, Ferricytochrome-C, and Ferrocytochrome-C. This is followed by determining detectability and optimum length-window of nanogap cavity of the proposed sensor device for the successful detection. Interestingly, it has been found that the undesired corner-effect, generally known for its unfavorable impact on the electrical behaviors of the MOS-based structures, actually comes to the aid by enhancing the detectability of the proposed device compared to its equivalent conventional SOI pTFET sensor device by almost 67% (for Protein-G, Ferricytochrome-C, and Ferrocytochrome-C) and 50% (for Apomyoglobin and Myoglobin) yet maintaining significantly good values for the sensitivity metrics throughout. Furthermore, smaller epilayer thicknesses ensure smaller optimum length-window of the nanogap cavity, resulting in more scaled-down device, compared to larger epilayer thickness values. A position-dependent variability study for the detectability also follows, and it has been found that for small epilayer thicknesses this dependency becomes large leading to less stable device, although, at the same time producing higher sensitivity metrics compared to the devices having large epilayer thicknesses. This makes the choice of channel epilayer thickness as application-specific.
1 citations
01 Jan 2021
TL;DR: In this article, a unique pTFET-based biosensor device having a channel epilayer has been introduced and its performance in the sensing domain has been studied through a rigorous analysis based on five different sensitivity parameters, followed by the determination of detectability of the proposed device and an optimum length-window of the nanogap cavity for the successful detection of five different types of bio-molecules.
Abstract: In the paper, for the first time, a unique pTFET-based biosensor device having a channel epilayer (epi-pTFET-biosensor) has been introduced and its performance in the sensing domain has been studied through a rigorous analysis based on five different sensitivity parameters, followed by the determination of detectability of the proposed device and an optimum length-window of the nanogap cavity for the successful detection of five different types of bio-molecules, viz., Protein-G, Ferrocytochrome-C, Ferricytochrome-C, Myoglobin, and Apomyoglobin. Interestingly, it has been found that the undesired corner-effect, generally known for its detrimental impact on the subthreshold characteristics of the MOS-based structures, when generated by the presence of a corner due to the introduced epilayer, actually, comes to the aid of the proposed epi-pTFET-biosensor device by enhancing its detectability, compared to its equivalent conventional SOI pTFET sensor device by a great degree, yet maintaining significantly good sensitivity matrices throughout.
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TL;DR: It is demonstrated that the sensitivity of NW-FET sensors can be exponentially enhanced in the subthreshold regime where the gating effect of molecules bound on a surface is the most effective due to the reduced screening of carriers in NWs.
Abstract: Nanowire field-effect transistors (NW-FETs) are emerging as powerful sensors for detection of chemical/biological species with various attractive features including high sensitivity and direct electrical readout. Yet to date there have been limited systematic studies addressing how the fundamental factors of devices affect their sensitivity. Here we demonstrate that the sensitivity of NW-FET sensors can be exponentially enhanced in the subthreshold regime where the gating effect of molecules bound on a surface is the most effective due to the reduced screening of carriers in NWs. This principle is exemplified in both pH and protein sensing experiments where the operational mode of NW-FET biosensors was tuned by electrolyte gating. The lowest charge detectable by NW-FET sensors working under different operational modes is also estimated. Our work shows that optimization of NW-FET structure and operating conditions can provide significant enhancement and fundamental understanding for the sensitivity limits ...
529 citations
TL;DR: The market entry for a new venture is very difficult unless a niche product can be developed with a considerable market volume, and miniaturization must be feasible to allow automation for parallel sensing with ease of operation at a competitive cost.
387 citations
TL;DR: The dielectric constants of myoglobin, apomyoglobin, the B fragment of staphylococcal protein A, and the immunoglobulin-binding domain of streptococcalprotein G are calculated from 1−2 ns molecular dynamics simulations in water, using the Frohlich−Kirkwood theory of dielectrics.
Abstract: The dielectric constants of myoglobin, apomyoglobin, the B fragment of staphylococcal protein A, and the immunoglobulin-binding domain of streptococcal protein G are calculated from 1−2 ns molecular dynamics simulations in water, using the Frohlich−Kirkwood theory of dielectrics. This dielectric constant is a direct measure of the polarizability of the protein medium and is the appropriate macroscopic quantity to measure its relaxation properties in response to a charged perturbation, such as electron transfer, photoexcitation, or ion binding. In each case the dielectric constant is low (2−3) in the protein interior, then rises to 11−21 for the whole molecule. The large overall dielectric constant is almost entirely due to the charged protein side chains, located at the protein surface, which have significant flexibility. If these are viewed instead as part of the outer solvent medium, then the remainder of the protein has a low dielectric constant of 3−6 (depending on the protein), comparable to that of ...
351 citations
TL;DR: In this paper, a novel solid-state sensor for charge detection in biomolecular processes is proposed, which is compatible with a standard CMOS process, thus allowing fully electronic readout and large scale of integration of biosensors on a single chip.
Abstract: A novel, solid-state sensor for charge detection in biomolecular processes is proposed. The device, called charge-modulated field-effect transistor, is compatible with a standard CMOS process, thus allowing fully electronic readout and large scale of integration of biosensors on a single chip. The detection mechanism is based on the field-effect modulation induced by electric charge changes related to the bioprocess. A model of the device was developed, to provide a manageable relationship between its output and geometric, design and process parameters. Extensive two- and three-dimensional simulations of the proposed structure validated the model and the working principle.
203 citations
TL;DR: 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.
Abstract: 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 (Vth) shift, variation in the on-current (Ion) level, and Ion/Ioff ratio. It has been shown that the TFET-based sensor shows a large deviation in the current level, and thus, change in Ion 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.
147 citations