Transient Current Peak Research Articles

Physics-based 3D simulation of single event transient current in GaN high-electron-mobility transistor and super-heterojunction field-effect transistor

Physics-based 3D simulations were conducted on a GaN high-electron-mobility transistor (HEMT) and a super-heterojunction field-effect transistor (SHJFET) to investigate the single event effect mechanism under heavy ion irradiation. Most of the single event transient current in HEMT was attributed to the punch-through effect in the bulk caused by the local increase in electrostatic potential. With improved E-field management and a more favorable potential profile to suppress source electron injection, the SHJFET had a 70% lower transient current peak value compared to the HEMT.

Sensitivity investigation of 100-MeV proton irradiation to SiGe HBT single event effect

The single event effect (SEE) sensitivity of silicon–germanium heterojunction bipolar transistor (SiGe HBT) irradiated by 100-MeV proton is investigated. The simulation results indicate that the most sensitive position of the SiGe HBT device is the emitter center, where the protons pass through the larger collector-substrate (CS) junction. Furthermore, in this work the experimental studies are also carried out by using 100-MeV proton. In order to consider the influence of temperature on SEE, both simulation and experiment are conducted at a temperature of 93 K. At a cryogenic temperature, the carrier mobility increases, which leads to higher transient current peaks, but the duration of the current decreases significantly. Notably, at the same proton flux, there is only one single event transient (SET) that occurs at 93 K. Thus, the radiation hard ability of the device increases at cryogenic temperatures. The simulation results are found to be qualitatively consistent with the experimental results of 100-MeV protons. To further evaluate the tolerance of the device, the influence of proton on SiGe HBT after gamma-ray (60Coγ) irradiation is investigated. As a result, as the cumulative dose increases, the introduction of traps results in a significant reduction in both the peak value and duration of the transient currents.

Investigation of single-event-transient effects on n+ pocket double-gate tunnel FET

This article investigates the response of double gate tunnel effect transistors (DG-TFETs) exposed to single-event effect (SEE) radiation. The radiation effects on different regions of DG-TFET are studied for various linear energy transfers (LETs) and drain voltages. The findings show that in both vertical and horizontal radiation, the channel and tunneling junction are the radiation-sensitive parts of DG-TFETs, respectively. To enhance radiation tolerance, an n + pocket is inserted at the source/channel junction to increase recombination and decrease the collected charges after irradiation. The results demonstrate that the n + pocket DG-TFET reduces the drain transient current peak under radiation by 23% compared to conventional DG-TFET. Furthermore, the incorporation of an n + pocket enhances the transistor's performance in multiple aspects. It not only reduces the subthreshold swing (SS) but also boosts the ON current (Ion) by a significant factor of 11 compared to the conventional DG-TFET.

A Bridge-Level Junction Temperature Estimation Method for SiC MOSFETs Combining Transient Voltage and Current Peaks

Accurate measurement of the junction temperature Tj is crucial for ensuring safe operation and evaluating the performance of silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors (MOSFETs). In this paper, the junction temperature of a half-bridge is monitored by combining transient voltage and current peaks across the lower device. Both theoretical analysis and switch tests validate that the peak induced voltage and peak reversed current during the commutation transient exhibit a linear relationship with the temperature of the corresponding devices. The impact of load current and bus voltage on the measurement results is also investigated. Moreover, the effectiveness of the proposed method is confirmed by carrying out tests at different temperatures, and the feasibility of online implementation is discussed. The experimental results show that the proposed method has high linearity and sensitivity and can simultaneously provide temperature information for both devices of a half-bridge.

Analysis of single event effects by heavy ion irradiation of Ga2O3 metal–oxide–semiconductor field-effect transistors

The model of lateral β-Ga2O3 metal–oxide–semiconductor field-effect transistor (MOSFET) was established using Sentaurus Technology Computer Aided Design software. The gate-to-drain distance of the device was 13.7 μm, and the breakdown voltage was 1135 V. The single event effect simulation model caused by heavy ion irradiation was introduced, and the effects of heavy ions’ incident position, angle, drain bias voltage, and linear energy transfer on the single event effect were studied. It is found that x = 7.7 μm is the sensitive location of the single event effect at the gate corner near the drain side and the peak value of the transient current is 177 mA/mm. The effect of the terminal structure of the field plate on the transient effect of the single event effect of β-Ga2O3 MOSFET is studied. It is also found that the sensitive position of the single event effect of the conventional structure, gate-field plate structure, and gate–source composite field plate structure is around x = 7.7 μm when VDS = 10 V. The peak transient currents obtained are 177, 161, and 148 mA/mm. The single event effect pulse current of the three structures increases with an increase in the drain bias voltage, while the peak pulse current of the conventional structure is larger than that of the gate-field plate structure and the gate–source composite structure. The research shows that the terminal structure of the field plate is reliable means to reduce the single particle effect.

An Analytical Prediction Model of Balanced and Unbalanced Faults in Doubly Fed Induction Machines

In this article, we present the exact transient solution to the unbalanced and balanced faults in the doubly fed induction machine (DFIM). Stator currents, rotor currents, and stator fluxes have been validated using simulation and experiment. The work is meant to strengthen and fasten the predictability of large DFIMs in the design stage to comply with mechanical constraints or grid fault issues. Moreover, the analytical approach reduces the computational costs of large-scale stability studies and is especially suited to the initial phase, where plethora design computations must be carried out for the DFIM before it is checked for its transient interaction with the power system. The possibility to dynamically estimate the DFIM performance is simplified by original equations derived from first principles. First, case studies of two large <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$265 \,{\rm MVA}$</tex-math></inline-formula> DFIMs are used to verify the analytical approach, and to justify the proposed “large machine approximation” using simulation with an exact match. Finally, laboratory measurements were conducted on a 10.96 and a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$1.94 \,{\rm kVA}$</tex-math></inline-formula> DFIM to validate the transient current peaks predicted in the proposed analytic expressions for two-phase and three-phase faults, respectively.

Optical reflectance studies on the oxidation of chemisorbed sulfur at the Pt(111) electrode

The oxidation of chemisorbed sulfur on Pt(111) was studied in 0.1 M H2SO4 using combined electrochemical and in situ optical reflectance. The adsorbed sulfur adlayer, prepared by immersion of the Pt electrode in Na2S solution, was successively removed by potential cycling between 0.05 and 1.22 V vs. RHE. Correlation of the electrochemical data with the parallel measured changes in optical reflectance provides insight into the intermediate steps of the sulfur oxidation process. In addition to features related to sulfur oxidation and Pt oxide formation and reduction, two transient cathodic current peaks at rather negative potentials (0.19 and 0.41 V) are observed the first cycles, which can be assigned to intermediates of the sulfur oxidation process. The sulfur coverage oxidized in each cycle is initially large but then decreases rapidly, becoming negligibly small after about 10 cycles. Furthermore, a nonlinear change of the reflectance with decreasing sulfur coverage is observed, which suggests changes in the nature of the S-Pt bond with coverage.

Single event effects prediction of MOSFET device using deep learning

Single event effect (SEE) is an important problem in the reliability research of integrated circuits. The study of SEE of traditional MOSFET devices is mainly based on simulation software, which is characterized by slow simulation speed, large computation and time-consuming. In this paper, a SEE research method based on deep learning is proposed. The method relies on 28 nm MOSFET. The complete drain transient current pulse, transient current peak value and total collected charge can be obtained in a short time by inputting relevant parameters that affect the SEE. The accuracy of the network for predicting transient current peak and total collected charge is 96.95% and 97.53% respectively, and the mean goodness of fit of the network for predicting the drain transient current pulse curve is 0.985. Compared with TCAD Sentaurus software, the simulation speed is increased by 5.89 × 103 and 1.50 × 103 times respectively. This method has good prediction effect and provides a new possibility for the study of SEE.

Effects of Inrush Current on the Hysteresis Loop and Load Influences on the Transient Current of a Single-Phase Transformer

When putting any unloaded transformer into service, a high-value current that can be very dangerous, called the inrush current, appears. The latter may cause problems and consequences in the electrical system. The challenges of visualizing the effects of transient regimes on the iron core's characteristics and the influence of the type of load on inrush current characteristics are covered in this study. The main purpose of this paper is to treat the influence of this transient phenomenon on the hysteresis loop of a single-phase transformer, in terms of its size, area, or position, and therefore, the influence of the load on the transient regime. A general study of the electromagnetic characteristics of the transformer iron core will be presented. Then, using the ATP-EMTP program, the purpose of the realized simulations is to visualize the relationship between the hysteresis loop and the magnetizing inrush current in the transient state. The results show the decrease of the hysteresis loop area and their shift with respect to the origin of the axes following the increase in the transient inrush current peak. As the second part of this article, there is a study of the influence of the load on the transient regime, i.e. inrush current. This is accomplished by adding a load with different configurations and various connections. The purpose is to find the effect of the load on the reduction of the transient inrush current phenomenon.

Analysis of location and LET dependence of single event transient in 14 nm SOI FinFET

FinFET, with narrow silicon fin, and high k/metal gate stacked combined with SOI technology brings benefits to radiation effects. Single event transient (SET) of SOI FinFET at 14 nm technology node is simulated by TCAD. The device model is calibrated by the experiment data. The effects of ion strike locations and linear energy transfer (LET) on SET are analyzed. The trends of the transient current peak, the collected charge, the deposited charge and the bipolar amplification are discussed. The results indicate that the most sensitive area of FinFET to SET is the gate-drain junction of fin. With LET increasing, the transient current peak and the collected charge increase while the bipolar amplification decreases.

22nm FDSOI SRAM single event upset simulation analysis

This article uses Sentaurus TCAD to establish the 3D device model of NMOS and PMOS under the 22nm FDSOI process, and establishes the 3D model of the 22nm FDSOI SRAM cell through this model. This model is used to numerically simulate the single event upset LET threshold of the 22nm FDSOI SRAM cell. The effects of different LET values and different incident conditions on the single event upset of a 22nm FDSOI SRAM cell are compared. The results show that whether the 22nm FDSOI SRAM cell is single event inversion depends on the transient current peak value generated after heavy ion incidence. For the 22nm FDSOI SRAM cell, the critical current peak value is about 0.011mA. Comparing the single event inversion thresholds at different incident positions, it is found that compared to the center of the channel, when a single event is incident on the channel-drain PN junction of an off-state N-type FDSOI device, the SRAM cell is more prone to single event inversion.

Single-Event-Induced Charge Collection in Ge-Channel pMOS FinFETs

Peak transient currents due to pulsed-laser or heavy-ion irradiation of Ge pMOS FinFETs are nearly independent of gate bias. This is because the prompt photocurrent is due primarily to a transient source-drain shunt. In contrast, long-term diffusion charge collection is strongly gate-bias dependent. This bias dependence results from hole injection from the source in response to the transient increase in electron concentration in the channel. The transients measured at the source terminal change polarity when the strike location moves from the source to the drain, but this effect does not occur for the transients measured at the drain terminal. Charge collection mechanisms are studied using TCAD simulations.

Effect of harmonic magnetic field and pulse magnetic field on microstructure of high purity Cu during electromagnetic direct chill casting

The effects of two types of magnetic fields, namely harmonic magnetic field (HMF) and pulse magnetic field (PMF) on magnetic flux density, Lorentz force, temperature field, and microstructure of high purity Cu were studied by numerical simulation and experiment during electromagnetic direct chill casting. The magnetic field is induced by a magnetic generation system including an electromagnetic control system and a cylindrical crystallizer of 300 mm in diameter equipped with excitation coils. A comprehensive mathematical model for high purity Cu electromagnetic casting was established in finite element method. The distributions of magnetic flux density and Lorentz force generated by the two magnetic fields were acquired by simulation and experimental measurement. The microstructure of billets produced by HMF and PMF casting was compared. Results show that the magnetic flux density and penetrability of PMF are significantly higher than those of HMF, due to its faster variation in transient current and higher peak value of magnetic flux density. In addition, PMF drives a stronger Lorentz force and deeper penetration depth than HMF does, because HMF creates higher eddy current and reverse electromagnetic field which weakens the original electromagnetic field. The microstructure of a billet by HMF is composed of columnar structure regions and central fine grain regions. By contrast, the billet by PMF has a uniform microstructure which is characterized by ultra-refined and uniform grains because PMF drives a strong dual convection, which increases the uniformity of the temperature field, enhances the impact of the liquid flow on the edge of the liquid pool and reduces the curvature radius of liquid pool. Eventually, PMF shows a good prospect for industrialization.

Calculation of Transient Torques on Motors During a Residual Voltage Motor Bus Transfer

To maintain a critical process upon loss of primary motor bus power, the petrochemical industry depends largely on residual voltage transfer, ignoring phase angle and closing the backup source when the motor bus residual voltage has decayed to 30%. To assess the consequences of out-of-phase residual voltage transfers, a transient simulation program models a bus with three motors of various sizes, inertias, and impedances. The three motors are loaded around 80% with fan, pump, and compressor loads to calculate the peak transient motor current and torque upon closure of the backup source breaker. Pre-transfer events and conditions produce an initial phase angle between the primary and backup sources, and the simulation reproduces the resultant residual voltage transfer closing angle and its effect on the peak transient current and torque. Individual motors exhibit positive and negative torques, oscillating from induction generator to motor, and the peak-to-peak torques are also recorded, as they can impact the motor shaft stress.

Investigation of Single Event Transient Effects in Junctionless Accumulation Mode MOSFET

The Junctionless Accumulation Mode Double Gate MOSFET (JAM DG MOSFET) is a promising novel architecture for future nano-scaled devices because of its outstanding electrical characteristics, e.g., lower subthreshold swing, lower drain induced barrier lowering, i.e., lower short channel effects and higher I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> /I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OFF</sub> ratio. In this paper, a comprehensive analysis of the effects of single-event transient on JAM DG MOSFET has been performed using the sentaurus TCAD simulator. The result shows that the transient drain current peak obtained after the heavy-ion strike for JAM DG MOSFET is small at lower value linear energy transfer (LET) and high for the larger value of LET. Collected charge at different LET values has also been investigated. Moreover, the sensitive region of the device, e.g., source to channel junction, channel, and channel to drain junction has been studied. It has been found that the drain to channel junction is more sensitive to the linear energy than the channel and source to channel junction. The electrical characteristics have also been compared with JL DG MOSFET.

Mitigation of Single-Event Effects in SiGe-HBT Current-Mode Logic Circuits.

It has been known that negative feedback loops (internal and external) in a SiGe heterojunction bipolar transistors (HBT) DC current mirrors improve single-event transient (SET) response; both the peak transient current and the settling time significantly decrease. In the present work, we demonstrate how radiation hardening by design (RHBD) techniques utilized in DC bias blocks only (current mirrors) can also improve the SET response in AC signal paths of switching circuits (e.g., current-mode logic, CML) without any additional hardening in those AC signal paths. Four CML circuits both with and without RHBD current mirrors were fabricated in 130 nm SiGe HBT technology. Two existing RHBD techniques were employed separately in the current mirrors of the CML circuits: (1) applying internal negative feedback and (2) adding a large capacitor in a sensitive node. In addition, these methods are also combined to analyze the overall SET performance. The single-event transients of the fabricated circuits were captured under the two-photon-absorption laser-induced single-event environment. The measurement data clearly show significant improvements in SET response in the AC signal paths of the CML circuits by using the two radiation hardening techniques applied only in DC current mirrors. The peak output transient current is notably reduced, and the settling time upon a laser strike is shortened significantly.

Study on the Charge Collection Mechanism of Single Event Transient Effect for Nano N-Channel Metal Oxide Semiconductor Field Effect Transistor

Based on the mechanism of charge collection, drift and diffusion, the influence of incident position, drain bias and incident particle LET (Linear Energy Transfer) value on the charge collection of NMOS devices is analyzed. It is found that the strongest electric field in drain depletion region is at 70 nm, and the maximum transient current is 3.43 mA. Drain bias affects the electric field in drain region. The higher drain bias is, the greater the electric field is, and the transient current is the larger of the peak value is, and the change of drain bias does not affect the diffusion current part; the larger the LET is, the larger the set current is, and the transient current peak value and collection charge increase linearly with the increase of LET. In addition, for a single transistor, the influence of the reduction of gate length on the bipolar amplification is analyzed, which is discovered that the reduction of gate length results in the aggravation of the single event effect. Therefore, the simulation results provide valuable reference for research on irradiation reliability and application of strained integrated circuit of Si Nano-scale NMOSFET.

Boost Converters’ Proximate Constrained Time‐Optimal Sliding Mode Control Based on Hybrid Switching Model

It is well known in the literature studies that the theoretical time‐optimal control of boost converters can be achieved using switching surfaces based on the converter’s natural state trajectories. However, this method has two important drawbacks: First, the transient current peak of the time‐optimal controller is far beyond the current limitations of related circuit elements in many practical cases. Second, switching based on the converter’s natural trajectories has high computational complexity and high dependence on circuit parameters. In this paper, based on the hybrid dynamical model of the converter and geometrical representation of its corresponding vector fields, a proximate constrained time‐optimal sliding mode controller is proposed. The proposed method has a fast response that is near that of a time‐optimal controller, with less computational complexity and sensitivity to parameter changes. The proposed method and its relevant theoretical framework are validated on an experimental setup with a boost converter prototype and an eZdsp TMS320F2812 processor board.

Effects of Temperature and Thiourea Addition on the Electrodeposition of Tin on Glassy Carbon Electrodes in Acid Solutions

The electrodeposition of tin on glassy carbon electrodes was studied in plain and thiourea-containing sulphuric acid solutions at different temperatures. Voltammograms exhibit a single cathodic current peak related to the electroreduction of tin ions on the glassy carbon substrate. The current of this peak increases linearly with the square root of the scan rate in the absence of thiourea, as expected for an electrochemical reaction under diffusion control. However, with the addition of thiourea, the peak current exhibits a semi-logarithmic dependence. Electrodeposition current transients show always a single peak that increases its height and appears at shorter times as the electrode potential is made more negative. The non-dimensional analysis of the current transients suggests the occurrence of an instantaneous nucleation and 3D growth under diffusion control in thiourea-free solutions. When thiourea is added, the transient current peak shifts to longer times and the non-dimensional analysis agrees with the presence of a progressive nucleation process. Seemingly, thiourea adsorbs on the electrode surface blocking active sites. This is consistent with the changes observed in the morphology of tin deposits, which change from well-distributed small crystallographic particles in the absence of thiourea, to complex and larger ones that exhibit branches at 900, in the presence of thiourea. Nyquist plots exhibit only two time constants at open circuit conditions, while in the potential range of tin electrodeposition two capacitive contributions appear at high an medium frequencies, followed by an inductance, assigned to a surface relaxation process, and a Warburg contribution, associated with the transport of ions to the interface, at low frequencies.

Permanent magnet fault current limiter for the power grid

With several significant advantages such as compactness, reliability, zero reset time, safe operation and fail safe, the permanent magnet fault current limiter (PMFCL) is a preferable solution to mitigate the fault current in power grids these years.In this paper, the substation voltage level PMFCL device, aims to extend the capacity of the power grid, is presented. The dry type PMFCL that does not require DC excitation coils is designed and simulated by 3D FEM. The 3D FEM magneto static solver has been used as time saving approach to predict the device fault current limitation in case of a fault. The peak transient currents simulation results were in agreement with the RMS values obtained using the magneto static inductance-current profile. The effect of the PMFCL on the fault current mitigation has been compared with an air-cored of similar specifications and a useful reduction in the fault current has been achieved.