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. 2025 Apr 30;15(1):15223.
doi: 10.1038/s41598-025-99817-9.

Ultra-sensitive heterojunction double gate BioTFET device for SARS-CoV-2 biomolecules detection

P Vimala  1 , A Sharon Geege  2 , N Mohankumar  3 , T S Arun Samuel  2 , T Ananth Kumar  4 , P Suveetha Dhanaselvam  5 , I Vivek Anand  2
Affiliations

Ultra-sensitive heterojunction double gate BioTFET device for SARS-CoV-2 biomolecules detection

P Vimala et al. Sci Rep. .

Abstract

The persisting SARS-CoV-2 genetic mutation could unintentionally increase human transmission, mortality, and aggravation. Since no specific pharmaceutical therapies or vaccinations exist, rapid detection and successful treatment are essential for managing the COVID-19 pandemic. BioTFETs exhibit superior sensitivity and faster response times than bioFETs, which are more vulnerable to substantial subthreshold swing and short-channel effects. This article presents the Dielectrically Modulated-Double Gate-Heterojunction-Tunnel FET-based biosensor (DG-bioHTFET) specifically engineered to identify and detect the nucleocapsid protein and RNA biomolecules with specific permittivity (k) of SARS-CoV-2 biomolecules embedded in the nanogaps. At Vgs = 1.5 V, the proposed device achieves a drain current (Ids) of 2.32 × 10- 5 A/µm. At k = 5 and k = 3.64, the ION/IOFF ratios are 3.550 × 105 and 3.403 × 105, respectively. The data suggest that the device exhibits increased sensitivity to biomolecules possessing elevated dielectric constants. It is feasible to design ultra-sensitive TFET biosensors as a bio-recognition unit, which offers the benefits of rapid label-free detection and high sensitivity. The device exhibits superior performance in terms of high drain current with enhanced sensitivity for precise biosensing applications.

Keywords: Double gate; Heterojunction; SARS-CoV-2; Sensitivity; Tunnel field effect transistor.

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Conflict of interest statement

Declarations. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Genomic sequence of SARS-C0V-2 virus.
Fig. 2
Fig. 2
Life cycle of SARS-CoV-2.
Fig. 3
Fig. 3
Calibrated results of experimental TFET vs. proposed DG-bioHTFET.
Fig. 4
Fig. 4
Schematic cross-section of DG-bioHTFET.
Fig. 5
Fig. 5
Tentative fabrication flow process of Double Gate Heterojunction Tunnel FET based biosensor (a) Substrate (b) Masking & photolithography deposition of Source & Drain material (c) Deposition of Channel material (d) Formation of oxide Layer and etching to form nanogaps (e) Formation of metallic contact.
Fig. 6
Fig. 6
Energy distribution(on-state) in label-free DG-bioHTFET.
Fig. 7
Fig. 7
Variation of potential across label-free DG-bioHTFET.
Fig. 8
Fig. 8
Electric field variation across label-free DG-bioHTFET.
Fig. 9
Fig. 9
Drain current variation across label-free DG-bioHTFET.
Fig. 10
Fig. 10
Drain current variation for different biomolecules in label-free DG-bioHTFET.
Fig. 11
Fig. 11
Sensitivity analysis for various biomolecules in label-free DG-bioHTFET.
Fig. 12
Fig. 12
Transconductance-gate ratio curves for different drain current values in label-free DG-bioHTFET.
Fig. 13
Fig. 13
Sensitivity variation for DG-bioHTFET against different k-values for cavity length variations in label-free DG-bioHTFET.
Fig. 14
Fig. 14
Comparison of DG-bioHTFET sensitivity analysis with existing work.
See this image and copyright information in PMC

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