Intrinsic Gain Research Articles

Performance Investigation of a Dielectric Stacked Triple Material Cylindrical Gate All Around MOSFET (DSTMCGAA) for Low Power Applications

This paper presents an analysis of gate stacked triple material dual-halo cylindrical MOSFET. The surface potential and electric field have been plotted for the proposed device using TCAD Silvaco at various channel lengths. The analytical model of surface potential, field and subthreshold current is also present. A comparative analysis has been accomplished for the proposed device with Asymmetric gate stack triple metal gate all around (AGSTMGAA), dual dielectric triple metal surrounding gate (DDTMSG) and Triple metal surrounding gate MOSFET. The performance metric of the device has been investigated in terms of Drain Induced Barrier Lowering (DIBL), Subthreshold swing and threshold-voltage roll-off. Furthermore, the analog behaviour of the device has been evaluated by determining transconductance, early voltage and intrinsic gain. The proposed device shows much better performance when compared to its counterpart. The mitigation in DIBL and leakage current indicates the cut back in the SCEs. The proposed device shows 8% improvement in SS, 36.2% improvement in DIBL and 13.5% improvement in threshold voltage roll-off as compared to AGSTMGAA. Hence, it can be used for low power applications.

Design and Performance Optimization of Junctionless Bottom Spacer FinFET for Digital/Analog/RF Applications at Sub-5nm Technology Node

This article for the first time reports the design and performance optimization of Junctionless (JL) Bottom spacer (BSP) FinFET. Initially to get the desired value of workfunction () and fin thickness (Tfin) for analog/RF analysis, the optimization of these parameters has been done by considering several values. It has been noticed that the increase in and reduction in Tfin can lead to better electrical performance with suppressed short channel effects (SCE). Further, it is also observed that reduction in bottom spacer height (HBSP) can fetch enhanced analog/RF performance considering the improvement noticed in transconductance (gm), intrinsic gain (AV), transconductance generation factor (TGF), cutoff frequency (fT), and Gain frequency product (GFP). Moreover, when the bottom spacer dielectric permittivity (KBSP) is increased from 3.9 to 22, it has been found that the analog/RF performance degrades significantly.

Efficient coding theory of dynamic attentional modulation.

Activity of sensory neurons is driven not only by external stimuli but also by feedback signals from higher brain areas. Attention is one particularly important internal signal whose presumed role is to modulate sensory representations such that they only encode information currently relevant to the organism at minimal cost. This hypothesis has, however, not yet been expressed in a normative computational framework. Here, by building on normative principles of probabilistic inference and efficient coding, we developed a model of dynamic population coding in the visual cortex. By continuously adapting the sensory code to changing demands of the perceptual observer, an attention-like modulation emerges. This modulation can dramatically reduce the amount of neural activity without deteriorating the accuracy of task-specific inferences. Our results suggest that a range of seemingly disparate cortical phenomena such as intrinsic gain modulation, attention-related tuning modulation, and response variability could be manifestations of the same underlying principles, which combine efficient sensory coding with optimal probabilistic inference in dynamic environments.

Extraordinarily Weak Temperature Dependence of the Drain Current in Small‐Molecule Schottky‐Contact‐Controlled Transistors through Active‐Layer and Contact Interplay

AbstractLow saturation voltages and extremely high intrinsic gain can be achieved in contact‐controlled thin‐film transistors (TFTs) with staggered device architecture, enabled by the energy barrier introduced at the source contact. The resulting device, the source‐gated transistor (SGT), is limited in its usefulness by the high temperature dependence of the drain current induced by the source energy barrier. Here, the interaction between the thermal characteristics of the source contact and the semiconductor to show drastically reduced temperature dependence for SGTs based on organic semiconductors (OSGTs) is exploited. This extraordinarily weak temperature dependence of the drain current is observed regardless of the height of the source energy barrier (27.8% in OSGTs with Ti contacts compared to 22.1% when using Au contacts, over a 34 K range). The reduction in mobility of the semiconductor offsets an increase in thermionic‐field emission of charge carriers at the source. This is a first for SGTs and provides a route to removing one of the last hurdles to their wider adoption. The OSGTs with Ti contacts also demonstrate: drain‐current saturation at very low drain‐source voltages (saturation factor of 0.22); noteworthy stability after 70 days; and minimal drain‐current variation with channel length or illumination.

Novel Combination 3DOF Radial/Axial Eddy-Current Position Sensor

A novel noncontact three-degree-of-freedom radial/axial eddy-current position sensor for applications in active magnetic bearings (AMBs) is developed. The sensor meets the most demanding industrial requirements, including ability to work in dusty environments and in many working fluids, low sensitivity to temperature changes, as well as external electrical and magnetic fields, excellent linearity over a large displacement range, large intrinsic gain, easy integration into a machine, robustness to variations in parameters of the external wiring, simplicity of the signal processing electronics, and large frequency bandwidth. The sensor is inexpensive in volume and well suited for high-volume production. It has been successfully integrated into a commercial 175-kW air compressor, which was spun to the full operation speed of 50 kRPM. Operation with a 4-m twisted-pair sensor cable has been demonstrated and using much longer (tens of meters) cables would be possible with design modifications. Even though the sensor was developed for AMBs, it can find other uses in rotating machinery and beyond.

N-Type Printed Organic Source-Gated Transistors with High Intrinsic Gain.

Source-gated transistors (SGTs) are emerging devices enabling high-gain single-stage amplifiers with low complexity. To date, the p-type printed organic SGT (OSGT) has been developed and showed high gain and low power consumption. However, complementary OSGT circuits remained impossible because of the lack of n-type OSGTs. Here, we show the first n-type OSGTs, which are printed and have a high intrinsic gain over 40. A Schottky source contact is intentionally formed between an n-type organic semiconductor, poly{[N,N'-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5'-(2,2'-bithiophene)} (N2200), and the silver electrode. In addition, a blocking layer at the edge of the source electrode plays an important role to improve the saturation characteristics and increase the intrinsic gain. Such n-type printed OSGTs and complementary circuits based on them are promising for flexible and wearable electronic devices such as for physiological and biochemical health monitoring.

0.6-V 1.65-μW Second-Order Gm-C Bandpass Filter for Multi-Frequency Bioimpedance Analysis Based on a Bootstrapped Bulk-Driven Voltage Buffer

A bootstrapping technique used to increase the intrinsic voltage gain of a bulk-driven MOS transistor is described in this paper. The proposed circuit incorporates a capacitor and a cutoff transistor to be connected to the gate terminal of a bulk-driven MOS device, thus achieving a quasi-floating-gate structure. As a result, the contribution of the gate transconductance is cancelled out and the voltage gain of the device is correspondingly increased. The technique allows for implementing a voltage follower with a voltage gain much closer to unity as compared to the conventional bulk-driven case. This voltage buffer, along with a pseudo-resistor, is used to design a linearized transconductor. The proposed transconductance cell includes an economic continuous tuning mechanism that permits programming the effective transconductance in a range sufficiently wide to counteract the typical variations that process parameters suffer during fabrication. The transconductor has been used to implement a second-order Gm-C bandpass filter with a relatively high selectivity factor, suited for multi-frequency bioimpedance analysis in a very low-voltage environment. All the circuits have been designed in 180 nm CMOS technology to operate with a 0.6-V single-supply voltage. Simulated results show that the proposed technique allows for increasing the linearity and reducing the input-referred noise of the bootstrapped bulk-driven MOS transistor, which results in an improvement of the overall performance of the transconductor. The center frequency of the bandpass filter designed can be programmed in the frequency range from 6.5 kHz to 37.5 kHz with a power consumption ranging between 1.34 μW and 2.19 μW. The circuit presents an in-band integrated noise of 190.5 μVrms and is able to process signals of 110 mVpp with a THD below −40 dB, thus leading to a dynamic range of 47.4 dB.

Opportunities of Si-microstrip LGAD for next-generation space detectors

Low Gain Avalanche Diode (LGAD) is a consolidated technology developed for particle detectors at colliders which allows for simultaneous and accurate time (<100 ps) and position (tens of μm) resolutions. It is a candidate technology that could enable for the first time 5D tracking in space using LGAD Si-microstrip tracking systems. The intrinsic gain of LGAD sensors may also allow to decrease the sensor thickness while achieving signal yields similar to those of Si-microstrips currently operated in Space. In this document we discuss the possible applications and breakthrough opportunities in next generation large area cosmic ray detectors and sub-GeV gamma-ray detectors that could be enabled by LGAD Si-microstrip tracking detectors in Space. We propose the design of a cost-effective instrument demonstrator on a CubeSat platform to enable and qualify the operations of LGAD Si-microstrip detectors in space.

Analog and RF performance optimization for gate all around tunnel FET using broken-gap material

Many times, the fabricated cylindrical gate-all-around tunnel FET (GAA TFET) has an uneven radius due to several etching and deposition processes involved while fabricating the device, which show notable variations in the performance of the device. In this report, III–V uneven GAA TFET is studied by considering the uneven radius as elliptical in shape for all possible variations, which shows a significant impact on analog and RF figure of merits (FOMs). The performance of the optimized devices is compared with their circular structure and with their maximum deviation in elliptical geometry for all possible variations in device channel and gate oxide. The variations in its device channel and gate oxide have shown a significant impact on the performance of the device. The analog and RF FOMs are studied, including the transconductance generation factor (gm/IDS), intrinsic gain (gmRO), capacitances (CGS, CGD), cut-off frequency (fT), and gate delay (τm).

Impact analysis of vacancy defects on Analog/RF performance parameters of GNR FET

The effects of vacancy defects, such as single vacancy defect (SVD) and di-vacancy defect (DVD) for low voltage, on the performance parameters of a dual-gated graphene nanoribbon (GNR) field-effect transistor (FET) are investigated and compared to an ideal GNR FET with no vacancy defect (zero vacancy). Self-consistent atomistic simulations are used to evaluate the performance parameters of the device based on the non-equilibrium Green's function (NEGF) formalism. Initially, the impact of vacancy defects on the analog and RF performance parameters is examined, and then a trade-off analysis is conducted between transistor efficiency and frequency. The results indicate that the di-vacancy device has the highest transconductance generation factor (TGF), output resistance, intrinsic gain, gate capacitance, power delay product, gain frequency product (GFP), and gain transfer frequency product (GTFP). In contrast, the highest transconductance value, transconductance frequency product (TFP) and cut-off frequency are obtained with the device without any vacancy defect.

Bottom metal strip based ferroelectric Schottky Barrier MOSFET

This study develops and simulates a novel Schottky Barrier MOSFET topology that enhances device performance. The suggested device makes use of a ferroelectric material, a metal strip, and a HfO2 layer. The use of high work function metal has significantly lowered the SB thickness due to which a considerable high ION (1.72 × 10-4 A/µm) and ION-IOFF ratio (1.72 × 105) is obtained in the suggested SB-MOSFET in contrast to conventional SB-MOSFET having ION=(3.77 × 10-6) A/µm and ION/IOFF = 2.37 × 102. In contrast to the traditional SB-MOSFET, it has been noticed that the cut-off frequency, intrinsic gain, gain bandwidth product, and gain transconductance frequency product have all significantly improved.

Tunnel-FET Evolution and Applications for Analog Circuits

In this work different generations of field effect tunneling transistor (TFET) are evaluated through DC digital and analog figures of merits. For TFET devices the main digital figure of merit is the subthreshold slope (SS), while for analog application the intrinsic voltage gain (AV) is the most important one. For the early generations, that are based on silicon, the SS does not reach values smaller than 60mV/dec at room temperature, however, the AV reaches values up to 80 dB, showing to be promising for analog applications. As the TFETs were being optimized for digital applications and consequently presenting better switching performance, the intrinsic voltage gain moves in the opposite direction. This opposite trend is related to which transport mechanism is predominant for each type of device. While III-V TFETs are more dependent on Band to Band Tunneling (BTBT), silicon devices are more relying on Trap-Assisted Tunneling (TAT). While BTBT allows for faster switching, TAT is less dependent on the drain electric field, so the former favors SS while the latter favors AV. Based on the good analog behavior of silicon channel TFETs, a two-stage operational transconductance amplifier (OTA) was designed with different TFET technologies and the compared results were discussed.

A comparative study on performance of junctionless Bulk SiGe and Si FinFET

In this paper, the n-type and p-type SiGe junctionless bulk FinFET (SiGe JL-FinFET) with a high Ge mole fraction (xF>0.8) was studied for characteristics of a single device and the CMOS logic circuit using 3D numerical simulation. A comparison study between SiGe JL-FinFET and Si JL-FinFET under 1×1019 to 5×1019 doping concentrations. The SiGe JL-FinFET exhibits a 28% and 9% enhancement of hole and electron mobility, thus the saturation current, transconductance, intrinsic gain, and intrinsic delay are improved up to 38%, 26%, 45% and 27% in the SiGe-based device as compared to the Si-based device. Due to the higher mobility and lower gate capacitance of SiGe JL-FinFET, the rise time, fall time, propagation delay, and maximum operating frequency of the CMOS inverter are also improved up to 34%, 13%, 9%, and 20%, respectively, compared to their Si-based counterparts. This SiGe junctionless device has a simple fabrication process and improvements in analog and digital performance at the sub-5 nm technology node, making this device a promising architecture for high-performance CMOS logic applications.

Performance Evaluation of Spacer Dielectric Engineered Vertically Stacked Junctionless Nanosheet FET for Sub-5 nm Technology Node

This manuscript for the first time provides insights on the impact of different spacer materials for the vertically stacked Junctionless Nanosheet Field Effect Transistor (JL-NSFET). The analog/RF performances of several single-k and dual-k spacers in two approaches namely (1) inner high-k + outer low-k and (2) inner low-k + outer high-k are explored at 3 nm gate length. It is noticed that the use of TiO2 spacer improves analog performance of the JL-NSFET whereas the usage of SiO2 improves the RF performance of the device when single-k spacer has been used. The intrinsic gain (Av) of the JL-NSFET is improved by ∼1.74× with TiO2 as compared to SiO2 spacer. Moreover, it is observed that the dual-k approach with inner high-k + outer low-k combination gives better analog/RF performances compared to inner low-k + outer high-k and single-k spacer combinations. Furthermore, the increase in length (Lsp,hk) of inner high-k spacer length provides improved analog characteristics at the marginal cost of RF performance.

Investigation of dopingless transistor with field plates for analog and digital applications

This work demonstrates the influence of introducing field plates to an electrostatically doped JLT (DLT) to maximize the gate control over its channel and apparently to suppress the GIDL effects as well as L-BTBT and off-state tunneling current (IOFF). Therefore, the parasitic BJT action is minimized significantly in the device by the application of field plates, which in turn, minimizes the tunneling current (IOFF) and improves the (ION/IOFF) current ratio by at least 2 orders. The on-state performance of the device is also improved and is analyzed by improved analog parameters such as Transconductance Gm (26%), intrinsic gain AV (70%), Output transconductance GDS (25.8%), Early voltage VEA (40.6%) and Output resistance R0 (34.63%) in comparison to conventional DLT. We have given a simplified fabrication flow for the proposed device and performed the misalignment analysis for the device. Moreover, the circuit level analysis of the device is examined on H-SPICE using lookup table model in Verilog-A.

Analogue tuning of junction-less strained DG-MODFET

This paper discusses an extensive investigation on the influence of work-function (WF) tuning on analogue properties of the n-type junction-less strained double-gate MOSFET. The investigation on the device has been conducted with fixed level of input parameters operating in saturation mode by taking the dependency of analogue properties on the WF tuning into account. Numerical simulation was performed using industrial-based process/device simulator, Silvaco TCAD tools. The simulation results revealed that analogue properties of the device such as transconductance (gm), transconductance generation factor (TGF), output conductance (gd) and early voltage (VEA) exhibited an increase of ~17.4%, ~104.7%, 96% and 69.4% respectively as the WF is slightly minimized. However, the output impedance (ro), and intrinsic gain (AV) were deteriorated for ~58.4% and ~16.2% respectively as the WF is slightly minimized.

A physics-based drain current model for Si1-xGex source/drain NT JLFET for enhanced hot carrier reliability with temperature measurement

In this paper, we report, the hot carrier reliability issue in the Si1-xGex source/drain nanotube (NT) junctionless field-effect transistor (JLFET) with temperature variations. The surface potential, electric field and drain current have been formulated by developing a physics-based analytical model. SiGe in the source/drain regions creates valence band discontinuity of ΔEg = 0.23 eV which significantly increases the tunneling width at the channel/drain interface and therefore, results in a diminished L-BTBT action. The results demonstrate that at T = 500 K, drain current with the influence of interface trap charges in the Si1-xGex S/D architecture shows better immunity than the conventional NTJLFET. The Si1-xGex S/D enhances the reliability of analog/RF parameters such as transconductance (gm), intrinsic gain (gm/gd), cut-off frequency (fT), and gain-transconductance-frequency-product (GTFP), against the hot carriers. We have also explored the reliability with germanium (Ge) content, x and observed that for Ge content above x = 0.3, the reliability degrades in terms of higher electron temperature, reduced gm, and lower fT. The analytical results are verified and are in good agreement with results of Sentaurus TCAD simulations. The Si1–xGex S/D architecture combined with NT core gate can help relieve the HCI trap charge reliability for JLFETs leading to significantly improved analog/RF parameters.

Gain-switching in CsPbBr3 microwire lasers

All-inorganic perovskite microwire lasers, which have intrinsic high material gain and short cavity, especially favor the generation of ultrashort optical pulses via gain switching for various potential applications. Particularly, the ultrashort gain-switched pulses may extend perovskite microwires to previously inaccessible areas, such as ultrafast switches, and chipscale microcombs pumping souces in photonic integrated circuits. Here, we show 13.6-ps ultrashort single-mode green pulses from the gain-switched CsPbBr3 microwire lasers under femtosecond optical pumping. The gain-switching dynamics is experimentally investigated by a streak camera system. The excitation fluence dependences of pulse width, delay time and rise time of the output pulses show good agreements with the rate equation simulations with taking gain nonlinearities and carrier recombination ABC model into account. Our results reveal that perovskite microwire lasers have potential for ultrashort pulse generation, while the low transient saturated gain, which may result from the high transient carrier temperature under femtosecond pumping is a significant limitation for further pulse shortening.

Resveratrol inhibits lipid and protein co-oxidation in sodium caseinate-walnut oil emulsions by reinforcing oil-water interface

Lipid-protein co-oxidation often causes nutrition loss, texture changes, and shortened shelf-life of emulsions. In this study, resveratrol significantly prevented lipid-protein co-oxidation in sodium caseinate (NaCas)-walnut oil emulsions, and the underlying mechanisms were explored in physical and chemical aspects. NaCas-walnut oil emulsions stabilized by resveratrol exhibited excellent physical stability at 55 °C for 12 days or at room temperature for 10 months due to forming a stable interfacial layer composed of resveratrol-modified NaCas. Furthermore, resveratrol binding caused NaCas structure’s partial unfolding and a ∼ 8% increase in hydrophobicity, in turn enhancing NaCas’ emulsification properties and electrostatic repulsion. Besides, more than 90% of resveratrol was loaded at the interface and enhanced NaCas’ Fe2+ chelating, DPPH scavenging abilities, and O2 quenching by ∼ 22.6%, 5.26 times, and 31.84%, respectively. Simultaneously, resveratrol significantly improved NaCas’ oxidative stability, as reflected by the decrease in adsorbed NaCas’ intrinsic fluorescence loss and protein carbonyls gain by ∼ 30% and 37%, respectively. Simultaneously, lipid hydroperoxides and TBARS were reduced by ∼ 30% and 20% in the NaCas-walnut oil emulsions containing 6 mM resveratrol than the control. Our findings contribute to further understanding of the possible interaction among lipid, protein, polyphenols, and their oxidative products at the oil–water interface, minimizing lipid-protein co-oxidation and extending functional oils’ shelf life. Finally, walnut oil emulsions with high physical and oxidative stabilities using resveratrol were prepared, further broadening resveratrol’s application in the food industry.

Evolutionary convergence of a neural mechanism in the cavefish lateral line system.

Animals can evolve dramatic sensory functions in response to environmental constraints, but little is known about the neural mechanisms underlying these changes. The Mexican tetra, Astyanax mexicanus, is a leading model to study genetic, behavioral, and physiological evolution by comparing eyed surface populations and blind cave populations. We compared neurophysiological responses of posterior lateral line afferent neurons and motor neurons across A. mexicanus populations to reveal how shifts in sensory function may shape behavioral diversity. These studies indicate differences in intrinsic afferent signaling and gain control across populations. Elevated endogenous afferent activity identified a lower response threshold in the lateral line of blind cavefish relative to surface fish leading to increased evoked potentials during hair cell deflection in cavefish. We next measured the effect of inhibitory corollary discharges from hindbrain efferent neurons onto afferents during locomotion. We discovered that three independently derived cavefish populations have evolved persistent afferent activity during locomotion, suggesting for the first time that partial loss of function in the efferent system can be an evolutionary mechanism for neural adaptation of a vertebrate sensory system.