Gating Characteristics Research Articles

Modeling the Behavior of a MOS Transistor under Fast Neutron and Gamma Irradiation

A numerical model of trapping of the radiation-induced charge in the bulk and on the surface of the oxide layer of a MOS transistor has been developed. The model takes into account the generation of point defects under fast neutron irradiation. The volume and surface charges obtained by the numerical modeling have been used to calculate the drain—gate characteristic of the MOS transistor exposed to neutron irradiation in different doses and accompanying high-energy gamma-ray irradiation. To model the effect of neutron irradiation, different methods for estimating the rate of point defect generation in a two-component material (SiO2) have been developed. The simulated drain—gate characteristic is shown to agree well with the experimental data obtained at the concentration of hole traps and their capture cross sections lying within the published data for an unirradiated device after exposure to gamma rays from a 60Co gamma source and after irradiation with fast neutrons with an average energy of ∼1 MeV and accompanying gamma rays using a pool-type reactor.

A matrix representation method for decoders using majority gate characteristics in quantum-dot cellular automata

Quantum-dot cellular automata (QCA) is a highly attractive alternative to CMOS for the future digital circuit design. Current methods for designing circuits in QCA, especially decoders, mainly refer to traditional CMOS circuit design methods, which do not make full use of the characteristics of QCA technology. For our purpose, the three-input majority gate in QCA is analyzed and a combinational logic gate that fully embodies the majority characteristics is then proposed. A matrix representation method for decoders using the logic gates is proposed, which combines matrix decomposition with majority characteristics. To verify the superiority of this method, a 2–4 and a 3–8 decoders are proposed and implemented in QCA. The proposed decoders have better physical properties in terms of area, latency, cell, gate count, power dissipation and cost function, compared with previous designs. In addition, a schematic diagram of a 4–16 decoder is also presented for demonstrating the scalability of this method. The experimental results show that this method is more suitable for the design of QCA decoders in contrast to previous methods, which can help to reduce the cost of QCA circuits.

3.6: High‐Reliability OLED Display Panel using Top Gate IGZO TFTs for 55inch UHD TVs

To improve electrical characteristics of top gate a‐IGZO TFT we have been optimized the oxygen in IGZO layer and decreased the excess oxygen of Gate Insulator layer. We achieved that the uniformity of threshold voltages of a‐IGZO TFTs on Gen. 8.5 glass is approximately 0.61V. Also, we achieved BTS characteristic about Δ0.1V at 2hr PBTS and Δ‐0.2V at 2hr NBTiS. In addition, we demonstrated the 55‐in 4K UHD OLED TV with high reliability Image sticking.

Breaking the boundaries between analogue and digital

breaking the boundaries between analogue and digital

How the calcium influx and homeostasis might be disrupted in the Purkinje cell degeneration and cerebellar dysfunction?

In cerebellar circuitry the Purkinje cells (PCs) are the most prominent neuronal element and are characterized by thick and highly branched dendritic tree. The signaling molecule PKCγ is critically linked to Purkinje cell function and has a strong negative impact on the dendritic growth and development of PCs. Recent evidence links enhanced PKCγ to long‐term alteration in calcium equilibrium in PCs. Observations also show that blocking the voltage gated calcium channels could partially or completely protect Purkinje cell dendrites from stunted growth thought to be associated with enhanced PKCγ activity. Additional evidence from moon walker mutant mice also link the increased calcium influx through TRPC3 channels to dampened dendritic morphology. In this study we investigate that how the calcium influx and homoeostasis is regulated in PCs? Here, we propose an integrated model of calcium equilibrium in PCs, by converging the mGluR1 induced membrane generation of DAG and calcium influx through TRPC3 channels into an integrated signaling cascade. The model proposed here link the DAG generation after membrane depolarization to PKCγ activation as well as the activation of TRPC3 through direct binding of DAG. This proposed signaling cascade suggests that DAG signaling in Purkinje cells is tightly regulated through a double‐negative feed‐back loop. The results show that DAG‐ PKCγ‐DGKγ axis forms the first negative feedback loop whereas, the DAG‐TRPC3‐PKCγ‐DGKγ axis forms the second negative feedback loop where, both PKCγ and DGKγ molecules in second negative feedback loop are contributing due to Ca+2 influx through TRPC3 channel, which in turn, stimulates the cytosol‐to‐membrane translocation of these molecules in PCs. Our results suggest that for wild‐type case the double negative feedback on DAG and subsequently on TRPC3 channel is exquisite and specific enough to maintain the calcium homeostasis in PCs, thus ensuring their viability. However, for PKCγ with enhanced activity the second double negative feedback loop is not able to tightly regulate the gating characteristics of TRPC3 channels thus disrupting the calcium homeostasis and leading to degeneration and dysfunction of PCs.Support or Funding InformationPrivate FundingThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Comparative Studies of AlGaAs/InGaAs Enhancement/Depletion-Mode High Electron Mobility Transistors with Virtual Channel Layers by Hybrid Gate Recesses Approaches

Unlike the conventional GaAs- and InP-based enhancement/depletion-mode (E/D-mode) transistors, the improved gate characteristics of the AlGaAs/InGaAs E-mode high electron mobility transistors (HEMTs) by way of hybrid gate recesses to remove the n-AlAs/i-GaAs/n-AlGaAs virtual channel layers upon 2DEG channels are demonstrated. As compared to the D-mode device (sample A), the gate reverse currents are effectively reduced by 45 and 102 times for the E-mode devices with additional gate recess time of 24 s (sample B) and 30 s (sample C) to remove part of the virtual channel layers, respectively. Under gate forward bias, the hybrid gate recesses also enable the gate turn-on voltages to increase. Furthermore, the threshold voltages of –1.25, 0.09, and 0.22 V are observed in the samples A, B, and C, respectively. The maximum transconductances of 187.3, 209.2, and 243.4 mS/mm and saturation current density of 482.8, 410.6, and 347.4 mA/mm are obtained in the samples A, B, and C, respectively.

DFT/NEGF study of discrete dopants in Si/III–V 3D FET

In this work, electron densities around dopants in Si and GaAs have been calculated using density functional theory (DFT) calculations. These extracted densities have been used to describe dopants in an in-house non-equilibrium Green functions device simulator. The transfer characteristics of nanowire gate all around field effect transistor have been calculated using DFT electron densities. These transport calculations were compared with those using a point charge model of the dopant. The dopants are located in the middle of the channel of the device. Specifically, DFT calculations of a 512 atom Si supercell with a single impurity atom have been carried out, both phosphorous and boron atoms have been used as donor and acceptor impurities respectively. The calculations were repeated on a gallium arsenide supercell, where the silicon atom substituted gallium and arsenide to act as donor and acceptor respectively. We found that for donors and acceptors, the DFT charge distribution extends similarly in both materials. In addition, the relaxed structure produces a 50% larger spread of electronic charge as compared with unrelaxed Si and GaAs. The extracted current voltage characteristics of the devices are altered significantly using the charge density obtained by DFT. At 0.7 V the current in Si is 20% larger using the DFT charge density compared to the point charge model for donors. Whereas the current using the point charge model in GaAs is 2.5 times larger than the distributed charge. Devices exhibit substantial tunnelling currents for donors and acceptors irrespective of the model of the dopant considered. In GaAs, this was 76% using a point charge and 78% using the distributed charge when using a donor; 61% and 68% in Si respectively. The tunnelling current using acceptors for Si was 100% and 99% using GaAs for both models.

Comparative Studies of AlGaAs/InGaAs Enhancement/Depletion-Mode High Electron Mobility Transistors with Virtual Channel Layers by Hybrid Gate Recesses Approaches -=SUP=-*-=/SUP=-

AbstractUnlike the conventional GaAs- and InP-based enhancement/depletion-mode ( E / D -mode) transistors, the improved gate characteristics of the AlGaAs/InGaAs E -mode high electron mobility transistors (HEMTs) by way of hybrid gate recesses to remove the n -AlAs/ i -GaAs/ n -AlGaAs virtual channel layers upon 2DEG channels are demonstrated. As compared to the D -mode device (sample A), the gate reverse currents are effectively reduced by 45 and 102 times for the E -mode devices with additional gate recess time of 24 s (sample B) and 30 s (sample C) to remove part of the virtual channel layers, respectively. Under gate forward bias, the hybrid gate recesses also enable the gate turn-on voltages to increase. Furthermore, the threshold voltages of –1.25, 0.09, and 0.22 V are observed in the samples A, B, and C, respectively. The maximum transconductances of 187.3, 209.2, and 243.4 mS/mm and saturation current density of 482.8, 410.6, and 347.4 mA/mm are obtained in the samples A, B, and C, respectively.

A Physical Model of an SOI Field-Effect Hall Sensor

Studies in the field of the development of new structures of Hall sensor with improved characteristics, in particular with increased magnetic sensitivity are in high demand. A physical model is proposed, which explains features of the Hall–hate characteristic and the formation of the increased magnetic sensitivity region in the SOI field-effect Hall sensor (SOI FEHS). The results of simulation in the Synopsys TCAD system confirm the proposed physical model of SOI FEHS functioning. The model explains features of the Hall–gate characteristic of the SOI FEHS in a wide range of gate voltages and allows the conclusion that the SOI FEHS has two operating regions and their choice is dictated by specific conditions of the sensor application. To achieve the maximum magnetic sensitivity, regions of partial depletion and enhancement should be chosen. To provide high noise immunity, it is reasonable to choose the full enhancement modes.

Assessing the role of residue E73 and lipid headgroup charge in VDAC1 voltage gating

The voltage-dependent anion channel (VDAC) is the most abundant protein of the mitochondrial outer membrane (MOM) where it regulates transport of ions and metabolites in and out of the organelle. VDAC function is extensively studied in a lipid bilayer system that allows conductance monitoring of reconstituted channels under applied voltage. The process of switching from a high-conductance state, open to metabolites, to a variety of low-conducting states, which excludes metabolite transport, is termed voltage gating and the mechanism remains poorly understood. Recent studies have implicated the involvement of the membrane-solvated residue E73 in the gating process through β-barrel destabilization. However, there has been no direct experimental evidence of E73 involvement in VDAC1 voltage gating. Here, using electrophysiology measurements, we exclude the involvement of E73 in murine VDAC1 (mVDAC1) voltage gating process. With an established protocol of assessing voltage gating of VDACs reconstituted into planar lipid membranes, we definitively show that mVDAC1 gating properties do not change when E73 is replaced by either a glutamine or an alanine. We further demonstrate that cholesterol has no effect on mVDAC1 gating characteristics, though it was shown that E73 is coordinating residue in the cholesterol binding site. In contrast, we found a pronounced gating effect based on the charge of the phospholipid headgroup, where the positive charge stimulates and negative charge suppresses gating. These findings call for critical evaluation of the existing models of VDAC gating and contribute to our understanding of VDAC's role in control of MOM permeability and regulation of mitochondrial respiration and metabolism.

Experimental investigation of discharge characteristics of float type sluice gate

Sluice gates are commonly used in canals for control and measurement of the flow. The discharge under sluice gates can be determined through different discharge methods. The present study proposed a new equation to accurately predict the discharge through floating type sluice gate by reading the depth of water at upstream of the gate and it reveals relationship between the gate opening and water depth. It also derived a theoretical equation for variations of sluice gate discharge coefficient under free flow condition. Effects of factors on discharge coefficient were investigated. This new model can be used to predict the performance of sluice gates with different sizes under free-flow situations.

Study on the Hydrodynamic Resistance Moment of Horizontally-Framed Miter Gates

Generally, the operation of the horizontally-framed miter gate in a ship lock should consider the effects of hydrodynamic resistance. If over-filling or over-emptying exists and the miter gate opens with reverse head, the hydrodynamic resistance will increase rapidly, endangering the operation safety of the miter gate. In order to study the operating characteristics of the miter gate, a prototype test is introduced in this paper. Results show that, during the filling or emptying process, when water levels at both sides of the miter gate are equal the first time, opening the gate in a timely manner can obviously avoid the influence of reverse head. Furthermore, a three-dimensional numerical model with a dynamic mesh is established for analyzing the hydrodynamic characteristics in different operating conditions. Results show that the peak value of operating load always occurs at the initial time, and the greater the submerged water depth, the larger the peak value. With the increasing of reverse head, the piston rods sustain a great compression, and the peak value appears at an early stage of gate opening. The results have a reference value for the design of a miter gate in the related engineering projects.

Flexible Neuromorphic Architectures Based on Self-Supported Multiterminal Organic Transistors.

Because of the fast expansion of artificial intelligence, development and applications of neuromorphic systems attract extensive interest. In this paper, a highly interconnected neuromorphic architecture (HINA) based on flexible self-supported multiterminal organic transistors is proposed. Au electrodes, poly(3-hexylthiophene) active channels, and ion-conducting membranes were combined to fabricate organic neuromorphic devices. Especially, freestanding ion-conducting membranes were used as gate dielectrics as well as support substrates. Basic neuromorphic behavior and four forms of spike-timing-dependent plasticity were emulated. The fabricated neuromorphic device showed excellent electrical stability and mechanical flexibility after 1000 bends. Most importantly, the device structure is interconnected in a way similar to the neural architecture of the human brain and realizes not only the structure of the multigate but also characteristics of the global gate. Dynamic processes of memorizing and forgetting were incorporated into the global gate matrix simulation. Pavlov's learning rule was also simulated by taking advantage of the multigate array. Realization of HINAs would open a new path for flexible and sophisticated neural networks.

Estimation of Threshold Voltage in SiC Short-Channel MOSFETs

In this brief, the influence of high-density traps at the SiO2/SiC interface on short-channel effects was investigated, and a model describing channel length dependence of the threshold voltage (i.e., the gate voltage at a given drain current) is proposed. First, we determined the densities of interface states and fixed charge in 4H-SiC n-channel MOSFET by fitting the calculated gate characteristics to the experimental data, and acquired the density of trapped electrons from the obtained results. Then, we calculated the threshold voltage by considering that the majority of the trapped electrons are emitted near the drain end due to formation of a depletion layer. The channel length dependence of the threshold voltage calculated by the proposed model showed a good agreement with the experimental results even when the definition of threshold voltage was changed. The present model taking account of the fixed charge and of the trapped electron charge enables the estimation of the threshold voltage in the 4H-SiC short-channel MOSFETs.

Directional gated imaging in a turbid medium using an ultrafast optical Kerr gate

Directional gated imaging of hidden objects in scattering media is demonstrated using an ultrafast optical Kerr gate (OKG), in which the gating and imaging beams are focused by utilizing a cylindrical lens and a convergent lens, respectively. Owing to the spatial transmission characteristics of the directional gate, a rectangular aperture stop is formed, which leads to different resolution limits for vertical and horizontal structures of an object. By implementing directional gated imaging, the directional feature can be extracted from an original image.

Gateways to Power and Paradise

Twin gate towers (que) were a characteristic feature of urban and palatial architecture in Chinese cities from the Warring States period onward. Although they initially served the practical military purpose of strengthening the defensive characteristics of gates in the city walls, they rapidly acquired symbolic significance through their association with political power. This article examines the development of twin towers from the Warring States period to the Eastern Han dynasty, showing how their ability to define political or sacred space was adapted to a variety of different social, political, and religious contexts, from city walls and palaces to imperial shrines and tombs. After the First Qin Emperor and Emperor Wu of the Han erected twin towers at the palaces they built in their pursuit of immortality, twin towers also became signifiers of the celestial realm. Finally, in the Eastern Han dynasty, the newly prominent merchant and local gentry classes who rose to assume political and administrative roles in the government adopted the architectural vocabulary of twin towers by constructing smaller-scale stone mimics at their own family tombs, appropriating the imperial prestige of this form to flaunt their social and financial success and construct their own identities as local elites. By examining this long historical development, I show how a functional element of urban architecture could acquire new symbolic meanings as different social and political actors adapted it to serve a wide variety of ends.

Functional characterization of Kv11.1 (hERG) potassium channels split in the voltage-sensing domain

Voltage-dependent KCNH family potassium channel functionality can be reconstructed using non-covalently linked voltage-sensing domain (VSD) and pore modules (split channels). However, the necessity of a covalent continuity for channel function has not been evaluated at other points within the two functionally independent channel modules. We find here that by cutting Kv11.1 (hERG, KCNH2) channels at the different loops linking the transmembrane spans of the channel core, not only channels split at the S4–S5 linker level, but also those split at the intracellular S2–S3 and the extracellular S3–S4 loops, yield fully functional channel proteins. Our data indicate that albeit less markedly, channels split after residue 482 in the S2–S3 linker resemble the uncoupled gating phenotype of those split at the C-terminal end of the VSD S4 transmembrane segment. Channels split after residues 514 and 518 in the S3–S4 linker show gating characteristics similar to those of the continuous wild-type channel. However, breaking the covalent link at this level strongly accelerates the voltage-dependent accessibility of a membrane impermeable methanethiosulfonate reagent to an engineered cysteine at the N-terminal region of the S4 transmembrane helix. Thus, besides that of the S4–S5 linker, structural integrity of the intracellular S2–S3 linker seems to constitute an important factor for proper transduction of VSD rearrangements to opening and closing the cytoplasmic gate. Furthermore, our data suggest that the short and probably rigid characteristics of the extracellular S3–S4 linker are not an essential component of the Kv11.1 voltage sensing machinery.

Solution structure of extracellular loop of human \u03b24 subunit of BK channel and its biological implication on ChTX sensitivity

Large-conductance Ca2+- and voltage-dependent K+ (BK) channels display diverse biological functions while their pore-forming α subunit is coded by a single Slo1 gene. The variety of BK channels is correlated with the effects of BKα coexpression with auxiliary β (β1-β4) subunits, as well as newly defined γ subunits. Charybdotoxin (ChTX) blocks BK channel through physically occluding the K+-conduction pore. Human brain enriched β4 subunit (hβ4) alters the conductance-voltage curve, slows activation and deactivation time courses of BK channels. Its extracellular loop (hβ4-loop) specifically impedes ChTX to bind BK channel pore. However, the structure of β4 subunit’s extracellular loop and the molecular mechanism for gating kinetics, toxin sensitivity of BK channels regulated by β4 are still unclear. To address them, here, we first identified four disulfide bonds in hβ4-loop by mass spectroscopy and NMR techniques. Then we determined its three-dimensional solution structure, performed NMR titration and electrophysiological analysis, and found that residue Asn123 of β4 subunit regulated the gating and pharmacological characteristics of BK channel. Finally, by constructing structure models of BKα/β4 and thermodynamic double-mutant cycle analysis, we proposed that BKα subunit might interact with β4 subunit through the conserved residue Glu264(BKα) coupling with residue Asn123(β4).

All-optical logic NOR gate using a single quantum-dot SOA-assisted an optical filter

We thoroughly explore the characteristics of an ultrafast all-optical NOR gate for 160 Gb/s return-to-zero Gaussian data signals using a single quantum-dot semiconductor optical amplifier (QD-SOA) and an optical filter (OF). In this proposed scheme, we employ an optical clock signal as a probe in addition to data signals as pumps between which the Boolean NOR function is executed. By conducting numerical simulations, we investigate and evaluate the effects of various critical factors on the extinction ratio and Q2-factor. This enables us to specify the margins of clock wavelength, peak power of data and clock signals, current density, electron relaxation time from the excited state to the ground state, linewidth enhancement factor, small signal gain of QD-SOA, OF bandwidth and order, the permissible extent of arrival time difference between data signals and clock, and the effect of amplified spontaneous emission. Moreover, we demonstrate that the proposed device can be applied to a multiple-input NOR gate. The results show that the proposed NOR gate can be achieved with both logical correctness and high quality when the specified conditions are satisfied.

A Scalable In-Memory Logic Synthesis Approach Using Memristor Crossbar

Because of their resistive switching properties and ease of controlling the resistive states, memristors have been proposed in nonvolatile storage as well as logic design applications. Memristors can be fabricated in a crossbar and suitable voltages applied to the row and column nanowires to control their states. This makes it possible to move toward new non-von Neumann-type architectures, usually referred to as in-memory computing, where logic operations can be performed directly on the storage fabric. In this paper, a scalable design flow for in-memory computing has been proposed, where a given multioutput logic function is synthesized as a netlist of NOT/NOR gates and then mapped to the crossbar using the Memristor-Aided loGIC (MAGIC) design style. The memristors corresponding to the primary inputs are initialized a priori. Subsequently, the required gate operations are performed by applying suitable row and column voltages in sequence. Two alternate mapping schemes have been analyzed. The switching characteristics of MAGIC NOR gates have been evaluated using circuit simulation under the Cadence Virtuoso environment. Experimental evaluation on ISCAS'85 benchmarks reports the average improvements of 27.7%, 34.6%, and 26.2%, respectively over a recently published work with respect to the number of memristors, number of cycles, and total energy dissipation, respectively. It may be noted that the energy consumption of the gates used in the proposed approach (NOT and NOR) is significantly higher than that using CMOS technology.