In this manuscript, an analytical model has been demonstrated for Dielectric Modulated Junctionless Biotube FET (DM-JL-BT-FET) as a sensor. The Junctionless Biotube FET based sensor has been compared with Nanowire FET under similar bio-molecule conditions. It has been demonstrated that Dielectric Modulated Junctionless Biotube FET shows much higher efficiency in Bio-sensing and poses superior device performance characteristic in terms of higher sensitivity, higher drift in drain current, transconductance, Ion/Ioff ratio, Subthreshold Slope and Threshold voltage. The hole concentrations have also been investigated under different biomolecule conditions. Two different biomolecule conditions have been considered in our analysis viz., firstly, varying the biomolecule concentrations and secondly, inserting different biomolecules namely DNA, Biotin and Hydroprotein. Improved bio sensing is observed in Junctionless Biotube FET because of superlative gate control over the channel, owing to architecture of Biotube FET. The analytical results have also been modelled for DM-JL-BT-FET by finding a solution to the 2-D Poisson equation in accordance with the boundary conditions. The analytical results are much in coherence with the results obtained from the simulator.

Dielectric Modulated Junctionless Biotube FET (DM-JL-BT-FET) Bio-Sensor

This work investigated the performance of overlapped gate-on-drain of a gate all around-tunnel field-effect transistor (GAA-TFET) biosensors by considering the dielectric modulated technique by immobilizing the targeted biomolecules in the cavity region curved under the overlapped gate-on-drain. The nanowire GAA-TFET device shows excellent controllability over the channel and reduces leakage current to a greater extent. Here, we tried to make the ambipolar nature of the TFET, an advantage for the biosensor by detecting the biomolecule using variation of ambipolar current of TFET. Due to structural arrangement, the nanocavity under the overlapped gate region suppresses the ambipolar drain current by increasing the dielectric constant of the targeted biomolecules. The device can show a variation of 102 and 103 amount of sensitivity for the variation of dielectric constant from 1 to 5 and, compared with the other TFET structure, the proposed overlapped gate-on-drain GAA-TFET biosensor shows higher sensitivity and low leakage with a highly controlled channel.

/pdf/nanowire-gate-all-around-tfet-based-biosensor-by-considering-28444hn37e.pdf

Nanowire gate all around-TFET-based biosensor by considering ambipolar transport

This paper presents a new field-effect sensor called open-gate junction gate field-effect transistor (OG-JFET) for biosensing applications. The OG-JFET consists of a p-type channel on top of an n-type layer in which the p-type serves as the sensing conductive layer between two ohmic contacted sources and drain electrodes. The structure is novel as it is based on a junction field-effect transistor with a subtle difference in that the top gate (n-type contact) has been removed to open the space for introducing the biomaterial and solution. The channel can be controlled through a back gate, enabling the sensor’s operation without a bulky electrode inside the solution. In this research, in order to demonstrate the sensor’s functionality for chemical and biosensing, we tested OG-JFET with varying pH solutions, cell adhesion (human oral neutrophils), human exhalation, and DNA molecules. Moreover, the sensor was simulated with COMSOL Multiphysics to gain insight into the sensor operation and its ion-sensitive capability. The complete simulation procedures and the physics of pH modeling is presented here, being numerically solved in COMSOL Multiphysics software. The outcome of the current study puts forward OG-JFET as a new platform for biosensing applications.

Electronic Sensing Platform (ESP) Based on Open-Gate Junction Field-Effect Transistor (OG-JFET) for Life Science Applications: Design, Modeling and Experimental Results

Investigation of AlGaN/GaN HEMT for pH sensing applications and sensitivity optimization

The emergence of gallium nitride high-electron-mobility transistor (GaN HEMT) devices has the potential to deliver high power and high frequency with performances surpassing mainstream silicon and other advanced semiconductor field-effect transistor (FET) technologies. Nevertheless, HEMT devices suffer from certain parasitic and reliability concerns that limit their performance. This paper aims to review the latest experimental evidence regarding HEMT technologies on the parasitic issues that affect aluminum gallium nitride (AlGaN)/GaN HEMTs. The first part of this review provides a brief introduction to AlGaN/GaN HEMT technologies, and the second part outlines the challenges often faced during HEMT fabrication, such as normally-on operation, self-heating effects, current collapse, peak electric field distribution, gate leakages, and high ohmic contact resistance. Finally, a number of effective approaches to enhancing the device’s performance are addressed.

https://www.mdpi.com/2072-666X/13/12/2133/pdf?version=1669902475

Challenges and Opportunities for High-Power and High-Frequency AlGaN/GaN High-Electron-Mobility Transistor (HEMT) Applications: A Review

This paper investigates the DC and RF performance of a gate field plate (GFP) and proposed grated gate field plate (GGFP) AlGaN/GaN high electron mobility transistor (HEMT) with a gate length of $$\mathrm{0.25}$$
 $$\upmu $$
 m through experimentally calibrated simulations. The GFP HEMT technology enhances breakdown voltage but influences the capacitive nature of the device with parasitic capacitance, particularly Miller’s capacitance, into action reducing its radio frequency and switching performance. To improve the electrical operation of a GFP HEMT, a grated gate field plate (GGFP) HEMT structure is proposed which exhibits operational improvements in terms of output current (1 A/mm), transconductance (350 mS/mm), and at the same time, reduces the parasitic capacitance effectively. We observe a 60% improvement in cut off frequency of the proposed GGFP HEMT (28.3 GHz) with respect to GFP HEMT (17.6 GHz) with little decrease in breakdown voltage. This study shows that the proposed device structure (GGFP HEMT) due to its effective capacitance reduction has better suitability and is a viable technique for future radio frequency applications.

Analysis of AlGaN/GaN HEMT and Its Operational Improvement Using a Grated Gate Field Plate

In this work, AlGaN/GaN high electron mobility transistor (HEMT) pH sensing simulation model is presented along with the sensitivity analysis to different pH values of an electrolyte by considering charged adsorbates systematically. Investigations were performed by studying the effect of pH values on device transfer characteristics and a smooth operation is observed with good pH resolution. The output current sensitivity is analyzed from both linear and saturation regions highlighting the response obtained at different drain bias. The device intricacies and sensing mechanism is also explained and demonstrated by analyzing the channel conductance, conduction band, potential profile and coupling capacitance along with the charge distribution profile at various interfaces using ATLAS Silvaco device simulation tool. The pH of solution is modelled by incorporating charged adsorbates as interface charge density at oxide-semiconductor interface in HEMT for the first time to best of our knowledge. The voltage sensitivity (SV) of 110 mV/pH was observed which is ~2 times beyond Nernst limit of sensitivity (59 mV/pH) and the current sensitivity (SI) is 17 mA/mm/pH which is 3 orders higher than silicon based devices. The effects of region of operation is also reported with a maximum upto 8 times higher sensitivity being observed in terms of maximum transconductance (gm) considerations and a near zero maximum gm was found to be optimum condition for higher sensitivity operation in reference electrode free configuration. Therefore high sensitive response along with better biocompatibility of AlGaN/GaN HEMT paves its way in next generation biosensing applications.

AlGaN/GaN HEMT pH Sensor Simulation Model and Its Maximum Transconductance Considerations for Improved Sensitivity

In this work, GaN/AlN/AlGaN MOS-HEMT with a cavity below the gate towards the drain side is studied for its sensitivity analysis and viability as a biosensor. The analysis is done by dielectric mod...

A Dielectrically Modulated GaN/AlN/AlGaN MOSHEMT with a Nanogap Embedded Cavity for Biosensing Applications

Here in this work, we demonstrate the concept of hybrid biosensor based on embedded cavity gate all around (GAA) junctionless field effect transistors (JLT) capable of sensing, amplification and noise cancellation simultaneously for the first time. The disadvantages of low sensitivity and noise in classical concept of single device biosensor system are mitigated using a hybrid scheme, where sensing is performed by p-type and n-type FETs simultaneously. The proposed hybrid biosensor is designed by exploiting dielectric modulation property of embedded nanogap cavity biologically sensitive field effect transistors (DM-FETs). Lookup table (LUT) based Verilog-A models are developed for p and n type devices considering various types of biosamples in the embedded nanogap cavity. The developed Verilog-A models are imbibed into Cadence Virtuoso to perform the circuit simulations. The biomolecules are simulated as dielectric materials with different permitivities in the embedded nanogap cavity. The proposed hybrid biosensor has been analyzed for different topologies and performance comparisons have been carried out between junctionless based DM-FET and inversion mode DM-FET based biosensors. The performance of proposed DM-FET based hybrid biosensor has been evaluated through voltage transfer characteristics (VTCs) in terms of logic threshold voltage shift (△VLt) and gain (AV). Performance comparisons for different topologies including resistive load, single stage and cascaded two stage hybrid biosensors have also been analyzed. Cascaded GAA JLT configured biosensors yields the highest △VLt sensitivity of 61.14%. However the results emphasize the superior all-round performance of cascaded CMOS configuration with $\triangle \text {V}_{\text {Lt}}\simeq 30\%$
 and gain AV = 55.

Aasif Mohammad Bhat

Papers

Analysis of AlGaN/GaN HEMT and Its Operational Improvement Using a Grated Gate Field Plate

AlGaN/GaN HEMT pH Sensor Simulation Model and Its Maximum Transconductance Considerations for Improved Sensitivity

A Dielectrically Modulated GaN/AlN/AlGaN MOSHEMT with a Nanogap Embedded Cavity for Biosensing Applications

Gate All Around Junctionless Dielectric Modulated BioFET Based Hybrid Biosensor

Investigation of AlGaN/GaN HEMT for pH sensing applications and sensitivity optimization