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This paper proposes a novel polarity-control junctionless tunnel field-effect transistor (PC-JL-TFET)-based biosensor for the label-free detection of biomolecule species in efficient ways. Unlike conventional designs, the polarity-control concept induces the generation of drain (n + ) and source (p + ) regions inside the proposed structure when a bias of ∓ 1. 2 V is applied at the polarity gates-1/2 (PG-1/2), to form a conventional TFET. To capture the biomolecules, a nano-cavity is created within the source region's dielectric oxide toward the tunneling interface. The presence of biomolecules is electronically detected based on either solely the dielectric constant (neutral biomolecules) or the combination of charge density and dielectric constant (charged biomolecules). The proposed device can perform label-free recognition of biomolecules such as Uricase, Keratin, Biotin, Streptavidin and so on. To investigate the sensing performance of the proposed biosensor, significant biosensing metrics such as the electric field, energy band diagram, tunneling current, subthreshold slope, I ON / I OFF ratio and threshold voltage have been studied. The proposed PC-JL-TFET biosensor achieves a maximum sensitivity of 5. 3 1 × 1 0 1 0 for neutral biomolecules with a dielectric constant of 12 and 1. 1 1 × 1 0 1 0 for negatively charged biomolecules (− 1 × 1 0 1 2 C/cm 2) with a dielectric constant of 8. The proposed biosensor's selectivity, linearity and temperature-based analysis have also been evaluated for different biomolecules. Additionally, real-time practical scenarios, such as partially filled nano-cavities and the random position of biomolecules in the nano-cavity-based analysis, have also been incorporated. [ABSTRACT FROM AUTHOR]

The fabrication complexity and cost associated with nanoscale devices are major concerns. Therefore, to address these challenges, we have introduced a mole fraction-based approach for the sensitivity analysis of a dual material control gate cavity on a source electrically doped polarity-controlled tunnel field effect transistor (DMCG-CS-ED-PC-TFET)-based biosensor for label-free detection of biomolecule species. For this purpose, a polarity bias (electrically doped) of PG- 1 = + 1. 2 V and PG- 2 = − 1. 2 V is applied for the formation of n+ drain and p+ source regions, respectively, over the thin silicon body. The proposed device structure overcomes the random dopant fluctuation issues, thereby avoiding thermal budget and fabrication complexity as compared to the conventional TFET. Moreover, the nanogap cavity is created by etching the appropriate portion at the source side oxide layer. Furthermore, we have applied a dual metal work function (M1 and M2) at the gate electrode along with hetero material Si 1 − X Ge X at the source side region to improve the sensitivity of the device by varying the mole fraction value (X). The performance of the proposed device has been evaluated in terms of variations in carrier concentration profile, electric field variation, energy band diagram, transfer ( I DS − V GS ) characteristics and the sensitivity in terms of drain current (I DS ), ON-state current (I ON ) and switching ratio (I ON /I OFF ). Furthermore, the sensitivity of the proposed device biosensor has been investigated by considering nanocavity dimensions, practical challenges such as various fill factors, and various step profiles generated from steric hindrance. For this purpose, different neutral biomolecules such as Biotin (k = 2. 6 3), APTES (k = 3. 5 7), Keratin (k = 8), Ferrocytochrome C (k = 4. 7) and Gelatin (k = 1 2) have been considered in the etched nanocavity region. Additionally, charged biomolecules with positive (negative) charge densities at the oxide semiconductor interface below the nanocavity region have been incorporated to assess the performance of the proposed device using the Silvaco ATLAS device simulator. In this analysis, the proposed biosensor achieves a drain current sensitivity of 5. 6 5 × 1 0 1 0 for neutral biomolecules (k = 1 2), 6. 2 × 1 0 1 0 for ρ = 1 × 1 0 1 2 cm − 2 with k = 1 2 and 1. 2 × 1 0 1 1 for ρ = − 1 × 1 0 1 2 cm − 2 and k = 1 2. Finally, the performance of the proposed biosensor, DMCG-CS-ED-PC-TFET, exhibits higher sensitivity compared to various existing TFET-based biosensors. Hence, the proposed biosensor exhibits the potential candidate for the development of future sensing bio-equipment. [ABSTRACT FROM AUTHOR]

In this paper, the applicability of dual material stacked gate-oxide-Pocket doped-hetero-junction tunnel field effect transistor (DMSGO-PD-HTFET) for low power switching and radio frequency (RF) applications is investigated. In this context, gate workfunction engineering, the stacked-gate-oxide ($$Si{O_2}$$ Si O 2 + $$Hf{O_2}$$ Hf O 2 ) approach, and asymmetrical doping at the P+ source ($$S{i_{1 - X}}G{e_X}$$ S i 1 − X G e X ) and N+ drain regions are considered. N+ pocket at source-channel interface implements DMSGO-PD-HTFET and improves interband tunnelling rate. This research aims to improve the device's switching ratio ($${I_{ON}}$$ I ON / $${I_{OFF}}$$ I OFF ), average subthreshold swing ($$S{S_{Avg}}$$ S S Avg ), and radio frequency (RF) performance. For this, the control gate work function, mole fraction (X), pocket thickness, and doping concentration are optimised. Next, the DC, analog/RF and linearity figure of merits of the proposed device is analysed and the performance is compared with conventional all-silicon dual-material stack gate oxide tunnel field effect transistor (DMSGO-TFET) and dual-material stacked gate oxide-hetero-junction tunnel field effect transistor (DMSGO-HTFET) with $$S{i_{1 - X}}G{e_X}$$ S i 1 − X G e X source using technology computer-aided design (TCAD) device simulator. Based on the comparative analysis, the optimised design with $$S{i_{0.6}}G{e_{0.4}}$$ S i 0.6 G e 0.4 exhibits an average subthreshold swing ($$S{S_{Avg}}$$ S S Avg ) of 28.8 mV/decade, switching ratio ($${I_{ON}}$$ I ON / $${I_{OFF}}$$ I OFF ) of 2 × 1012, cut-off frequency ($${f_T}$$ f T ) of 216 (GHz), and other significant improvements in analog/RF and linearity performance parameters. The proposed device is therefore suitable for switching and RF applications. [ABSTRACT FROM AUTHOR]

In this paper, the performance of dual-material stacked gate oxide-source dielectric pocket-tunnel field-effect transistor (DMSGO-SDP-TFET) has been investigated by considering fixed interface trap charges (ITCs) at the Si–SiO2 interface. During the analysis, both types of trap charges, positive (donor) and negative (acceptor), have been considered to investigate their effect on the DC, analog/ radio frequency, linearity and harmonic distortion performance parameters in terms of the carrier concentration, electric field, band-to-band tunneling rate, transfer characteristics, transconductance ( g m ), unity gain frequency ( f T ), gain–bandwidth product, device efficiency ( g m / I DS ), transconductance frequency product, transit time (τ), second- and third-order transconductance and voltage intercept points ( g m 2 , g m 3 , VIP2 and VIP3), third-order Input Intercept Point and Intermodulation Distortion (IIP3, IMD3), second-, third-order and total harmonic distortions (HD2, HD3 and THD), respectively. Further, the impact of temperature variations from 2 0 0 K to 5 0 0 K in the presence of ITCs is investigated and the results are compared with conventional DMSGO-TFET. In terms of percentage variation, DMSGO-SDP-TFET depicts lower variation than conventional DMSGO-TFET, indicating that the proposed device is more immune to trap charges and can be used for energy-efficient, high-frequency and linearity applications at elevated temperatures. [ABSTRACT FROM AUTHOR]