Two-dimensional MoS2 negative capacitor transistors for enhanced (super-Nernstian) signal-to-noise performance of next-generation nano biosensors

Abstract

The successful detection of biomolecules by a Field Effect Transistor-based biosensor (BioFET) is dictated by the sensor's intrinsic Signal-to-Noise Ratio (SNR). The detection limit of a traditional BioFET is fundamentally limited by biomolecule diffusion, charge screening, linear charge to surface-potential transduction, and Flicker noise. In this paper, we demonstrate that the recently introduced transistor technology called Negative Capacitor Field effect transistor (NCFET) offers nonlinear charge transduction and suppression of Flicker noise to dramatically improve the SNR over classical Boltzmann sensors. We quantify the SNR improvement by interpreting the experimental results associated with the signal and noise characteristics of 2D MoS2-based transistors. The combined sensitivity enhancement and noise rejection guarantee a high SNR of the NC-BioFET, making this device a promising candidate for realizing advanced integrated nanobiosensors. KEYWORDS 2D MoS2 FETs, Negative Capacitor Transistors, Nano Biosensors, Signal-to-Noise Ratio (SNR), Nonlinear response, SensitivityMany research groups worldwide are focused on developing highly sensitive, fast responding, and selective transistor-based biosensors. These sensors, known as BioFETs, allow label-free detection of biomolecules with the Limit of Detection (LOD) in the nano-and pico-molar concentration ranges 1 , potentially enabling many applications in personalized medicine 2 , early detection of diseases 3 , genome sequencing 4,5 , etc. A BioFET relies on the modulation of surface potential due to the charged biomolecules adsorbed on the gate electrode. Thus, the fundamental sensitivity limit of BioFETs depends on the diffusion of biomolecules 6 , surface charge screening, and linear "charge-to-surface potential" relationship 7 . These limitations apply to all FET-based biosensors, e.g. Dual-Gate FET 8 ; Silicon Nanowire *

A memory window expression to evaluate the endurance of ferroelectric FETs

“…where Q s is the semiconductor charge, α, β are the Landau parameters for the ferroelectric layer, ε FE is the parameter accounting for the dielectric response of the ferroelectric layer 16,17 3) reflect the contributions to the displacement of the electric field (D) obtained from the spontaneous polarization and the applied electric field 16 , i.e., D = ε F E E + P. Incidentally, we mention that the LD formulation of C FE is commonly employed to describe the operation of Negative Capacitance transistors (NCFETs) for logic 15 and other applications (such as bio-sensing 18 ). However, it can be used also to model the operation of hysteretic FeFETs 13 .…”

Scalably Nanomanufactured Atomically Thin Materials‐Based Wearable Health Sensors

“…2D semiconducting materials nevertheless suffer from intrinsically high electrical noise due to the reduced conductivity. [ 888–890,890–893 ] Achieving a co‐optimized responsivity and SNR has also been intensively pursued 2D material‐based gas sensors. [ 890–893 ] For example, to obtain an ultrahigh SNR in 2D materials‐based gas sensors, Raghu et al [ 893 ] developed a TiO 2 grafted 2D TiC nanosheets (TiO 2 /2D‐TiC)‐based ethanol gas sensor with an SNR of 18, 961, higher than the pure TiO 2 (8.3) and 2D‐TiC (339) because TiO 2 generates more surface groups for chemical adsorption of oxygen, making the TiO 2 /2D‐TiC nanosheets more sensitive to ethanol gas molecules.…”

“…[ 888–890,890–893 ] Achieving a co‐optimized responsivity and SNR has also been intensively pursued 2D material‐based gas sensors. [ 890–893 ] For example, to obtain an ultrahigh SNR in 2D materials‐based gas sensors, Raghu et al [ 893 ] developed a TiO 2 grafted 2D TiC nanosheets (TiO 2 /2D‐TiC)‐based ethanol gas sensor with an SNR of 18, 961, higher than the pure TiO 2 (8.3) and 2D‐TiC (339) because TiO 2 generates more surface groups for chemical adsorption of oxygen, making the TiO 2 /2D‐TiC nanosheets more sensitive to ethanol gas molecules. The TiO 2 /2D‐TiC gas sensor showed a LOD of 10 ppb toward ethanol gas and was proved to be stable after 5 months of storing under the ambient environment with only 0.7% drift of response toward 1 ppm ethanol gas, showing the possibility of using the TiO 2 /2D‐TiC gas sensor for long‐term wearable monitoring of gases.…”

Internal Electrical Noises of BioFET Sensors Based on Various Architectures

“…The detection limit of a traditional BioFET is fundamentally limited by biomolecule diffusion, charge screening, linear charge to surface-potential transduction, and flicker noise (1 f -noise). In [71] McAndrew with coauthors shows how correlated noise can be implemented in Verilog-A, and presents a new and simple technique to simulate the noise correlation coefficient using only the standard Space noise analyses [72]. An analytic proof is given that the noise contributed by the distributed gate resistance of the MOSFET can be modeled by including a gate resistance of value 3 g R in series with the gate capacitance.…”