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关键词： SiC MOSFET   SBD   neural networks  

摘要： The SiC MOSFET with an integrated SBD (SBD-MOSFET) exhibits excellent performance in power electronics. However, the static and dynamic characteristics of this device are influenced by a multitude of parameters, and traditional TCAD simulation methods are often characterized by their complexity. Due to the increasing research on neural networks in recent years, such as the application of neural networks to the prediction of GaN JBS and Finfet devices, this paper considers the application of neural networks to the performance prediction of SiC MOSFET devices with an integrated SBD. This study introduces a novel approach utilizing neural network machine learning to predict the static and dynamic characteristics of the SBD-MOSFET. In this research, SBD-MOSFET devices are modeled and simulated using Sentaurus TCAD(2017) software, resulting in the generation of 625 sets of device structure and sample data, which serve as the sample set for the neural network. These input variables are then fed into the neural network for prediction. The findings indicate that the mean square error (MSE) values for the threshold voltage (Vth), breakdown voltage (BV), specific on-resistance (Ron), and total switching power dissipation (E) are 0.0051, 0.0031, 0.0065, and 0.0220, respectively, demonstrating a high degree of accuracy in the predicted values. Meanwhile, in the comparison of convolutional neural networks and machine learning, the CNN accuracy is much higher than the machine learning methods. This method of predicting device performance via neural networks offers a rapid means of designing SBD-MOSFETs with specified performance targets, thereby presenting significant advantages in accelerating research on SBD-MOSFET performance prediction.

关键词： Silicon carbide   Sensors   Computational modeling   Mathematical models   MOSFET   Analytical models   Time-domain analysis   Analytic model   bidirectional charger   CLLC converter   SiC   synchronous rectifier (SR)  

摘要： It is extremely important to use synchronous rectifier (SR) as the diode forward voltage of SiC mosfets may be up to six times higher than Si mosfets, which causes much higher conduction loss. Conventional CLLC SR typically uses detection circuits or builds complex models, but they are susceptible to high dv/dt generated from SiC devices, or have difficulty in implementing SR online due to the complex numerical calculation. A digital real-time computation SR algorithm is proposed for bidirectional SiC CLLC converter. Analytic models in the time domain are constructed to calculate the SR conduction time online. It not only achieves low conduction loss by optimizing the on-time of SR MOSFETs, but also provides high immunity to the high switching frequency noise. A prototype of 300-kHz 6.6-kW SiC bidirectional CLLC charger was built to verify the proposed control. With the proposed SR, the CLLC efficiencies are up to 97.56% and 97.75% at full load in the forward and reverse modes, respectively. Moreover, the CLLC full load efficiencies improves 0.42% and 0.35% over the conventional SR control in the forward and reverse modes. The power density of proposed charger increment is also up to 20% over Wolfspeed charger.

关键词： MOSFET devices   Packaging hardening   High-entropy alloy   Lattice shrinkage   Irradiation stability  

摘要： The limited irradiation stability of metal-oxide-semiconductor field-effect transistor (MOSFET) devices has restricted their application in deep space exploration missions. Therefore, it is an urgent need to develop a new and efficient packaging hardening techniques to improve the irradiation stability of MOSFET devices. Herein, Cr0.5NbMoTaW was prepared by localized high-energy mechanical alloying and coated on the MOSFET's surface, and the packaged MOSFETs exhibit excellent irradiation stability. The threshold voltage change value of Cr0.5NbMoTaW packaged MOSFET device (0.26 V) is lower than the unpackaged MOSFET (4.15 V) after highenergy electron irradiation. Experimental and theoretical calculations show that Cr induces lattice shrinkage of Cr0.5NbMoTaW high-entropy alloys, leading to an improved density of nucleus. This increases the probability of elastic and inelastic collision between high-energy electrons and the nucleus, thus achieving excellent irradiation stability of packaged MOSFET devices. This work presents a strategy to improve the irradiation stability of MOSFET devices by using high-entropy alloy packaging.

关键词： Analytical model   metal-oxide-semiconductor field-effect transistor (MOSFET)   silicon carbide (SiC)   switching characteristics   temperature-dependent modeling  

摘要： In this article, a temperature-dependent transient model of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (mosfet) is proposed. The switching transient of the SiC mosfet is divided into four phases. In each phase, the operations of the mosfet and its body diode are analyzed and the corresponding equivalent circuits are obtained. The analysis identifies that the C-gd x dV(ds)/dt and L-s x dI(d)/dt induced negative feedback mechanisms, excess charge extraction in the N-base of SiC mosfet body diode and dynamic transfer characteristics at switching transient are pivotal physical characteristics. The dependence of junction temperature T-J1 of low-side mosfet and junction temperature T-J2 of high-side mosfet on the switching behavior of SiC mosfet is also analyzed and included in the proposed model. Based on the improved understanding of the switching behavior, an analytical model of SiC mosfet is derived. The analytically derived switching waveforms and switching losses are compared to the test data and good agreement is obtained.

关键词： Silicon carbide (SiC)   High-K dielectric   Schottky barrier diode (SBD)   Short-circuit withstand time   Figure-of-merit ( FOM )  

摘要： A novel 1.2-kV double-trench SiC MOSFET with stepped Schottky barrier diode (SBD) (DTSS-MOS) has been proposed and studied. The proposed device employs a deep gate trench filled with high-K dielectric and a shallow source trench with stepped SBD to modulate the electric field distribution, causing a higher figure-of-merit (FOM). After optimizing the structural parameters, the FOM of the DTSS-MOS improves by 266 % and 47 % compared to the planar-gate MOSFET (PG-MOS) and the trench-gate MOSFET (TG-MOS), respectively. Meanwhile, due to its lower specific on-resistance (Ron,sp), the DTSS-MOS exhibits an outstanding high-frequency figure of merit (HFFOM). Furthermore, the shallow source trench incorporates the stepped SBD, allowing the P-well region and P+ shielding layer to effectively reduce the electron flowing path in the SBD region, thereby lowering the temperature and enhancing the short-circuit withstand time (SCWT). The SCWT of the DTSS-MOS is increased by 75 % and 133 % compared with PG-MOS and TG-MOS, respectively. Additionally, a feasible process flow for the DTSS-MOS is provided.

关键词： Silicon carbide   Voltage   Switches   Silicon   Schottky diodes   MOSFET   Inductors   Capacitors   Rectifiers   Gate drivers   Current source converter   current source rectifier   current source inverter   current switch   medium voltage   reverse voltage-blocking   silicon carbide   CSC   CSR   CSI   CS   MV   RVB   SGCT   SiC  

摘要： Current source converters (CSCs) find extensive applications in medium voltage (MV) motor drive systems, ranging from 100 kWs to 10 s of MWs. In conventional CSC motor drives, Symmetric Gate-Commutated Thyristors (SGCTs) serve as reverse voltage-blocking (RVB) switches, referred to as current switches (CS). However, these SGCT devices operate at relatively low switching frequencies (420-720 Hz), leading to larger passive components and reduced system efficiencies. Furthermore, these devices must be connected in series to achieve the necessary line-line voltage ratings of 4.16 kV for 4.16 kV-rated motors. The emergence of Silicon Carbide (SiC)-based devices has revolutionized CSC technology by enabling high switching frequency, reducing the size of the passives, and the need for a high device count. This paper presents a comparative study between a single 10 kV SiC CS and two series-connected 6.5 kV SGCTs for MV CSC applications with a line-to-line voltage rating of 4.16 kV. The analysis encompasses device sizing, passive component selection and sizing, and the evaluation of system losses, including converter losses and passive component losses. The results highlight the advantages of the SiC-based solution, which offers increased power density, improved waveform quality with reduced total harmonic distortion (THD), enhanced overall system efficiency, and higher thermal limits. Finally, experimental results with the 10 kV XHV-9 module are presented.

关键词： Switching frequency   Electromagnetic interference   Serial chopper   Differential mode   Common mode  

摘要： Static converters consist of electronic switches, passive components (inductor, capacitor), and resistors, allowing the conversion of electrical energy from one form to another. However, the uses of semi-conductor components (MOSFET, IGBT, Thyristor, etc.) in switching are generating rapid variations of voltage (dv/dt) and current (di/dt). This leads to high-frequency electromagnetic disturbances. This paper presents the study of electromagnetic disturbances conducted in common and differential modes in a series chopper by simulation using LTspice software. Experimental measurements validate the obtained results. Then, we studied the impact of variation of the switching frequency on the input current and the output voltage of the chopper, as well as on the disturbances conducted in two modes, common mode, and differential, by experimental measurements in the time and frequency domains. An Arduino program does these variations on the control signal parameters.

关键词： Switches   Timing   Logic gates   Oscillators   Silicon carbide   MOSFET   Transient analysis   Active gate driver   current sharing   electromagnetic interference (EMI)   half bridge module   parallel devices   Silicon Carbide (SiC)  

摘要： Silicon Carbide mosfets offer increased switching speeds, reduced filtering component sizes and lower switching losses when compared to Silicon IGBTs in power converters. However, available module current ratings, increased oscillatory switching behavior, large drain-source voltage overshoots, and high output voltage dV/dt levels are all limiting factors to their adoption in medium to high-power applications. The use of inter-device inductances with switching edge skewing has previously been demonstrated as a method of limiting current imbalances when paralleling modules. This article shows that by precisely controlling the timing skews applied between modules in such arrangements, substantial overshoot, oscillation, and output voltage dV/dt reductions can also be achieved. In addition, if current feedback is included, the module switching order can be varied to facilitate a fixed-skew active current balancing strategy. The mechanisms behind all of these effects are analyzed in detail, focusing on the impact of applied timing skew, and inter-device inductance on the improvements. An experimental investigation validating the current balancing, switching performance improvements, and reduced output voltage dV/dt is also presented using 400 A 1.2 kV half-bridge modules, with up to 4 modules in parallel at a total load current of 1600 A.

关键词： MOSFET   Logic gates   Performance evaluation   Silicon-on-insulator   Heating systems   Substrates   Silicon   Transmission electron microscopy   Nanoscale devices   Fabrication   Heat sinking capability   nanoscale-embedded chamber   total ionizing dose (TID) hardening   void-embedded silicon on insulator (VESOI)  

摘要： The excellent tolerance against total ionizing dose (TID) effect and high compatibility with conventional technology nodes has been demonstrated in our previous work with void-embedded-silicon-on-insulator (VESOI) device. However, the presence of embedded void structures within the VESOI devices also introduces additional thermal performance challenges. To address this issue while maintaining the exceptional TID tolerance, we conducted a comprehensive study on the role played by embedded void in blocking both thermal conduction and radiation induced leakage path. Through both pulse I-V tests and systematic simulations, we have revealed the close relationship between the heat sinking capability of VESOI devices and the embedded voids with different structures and dimensions. By applying a nanoscale-embedded chamber extending into the middle channel of VESOI MOSFET, the increase of temperature in the channel is suppressed to a rather low level of 0.3 K. Furthermore, the nano void chamber is also found effective in cutting off radiation-induced leakage paths lying near the bottom channel, resulting in a reduction of the leakage current to 10 $<^>{-\text{11}}$ $\mu$ A/ $\mu$ m. This study paves the way for developing more robust and efficient devices based on VESOI technology that can maintain better thermal performance along with TID robustness.

关键词： electromagnetic interference   loss measurement   MOSFET   power semiconductor devices   semiconductor device measurement   semiconductor device packaging   semiconductor device reliability   semiconductor device testing   silicon compounds   switching transients  

摘要： Switching transient processes of silicon carbide (SiC) devices induce several challenges, such as voltage and current overshoots, switching losses, dv/dt, di/dt, and electromagnetic interference (EMI), threatening the safe and efficient operation of power electronic systems. Characterization of SiC modules is crucial to address these issues. This paper characterizes the dynamic and EMI performance of a state-of-the-art 1.2kV/100A all-SiC module with the Easy-2B package from Fuji Electric. Using a double pulse test (DPT) platform, the dynamic characteristics are assessed across varying load conditions and gate resistances. Additionally, EMI characteristics of the module are evaluated in a semi-anechoic chamber. Results indicate significant impacts of gate drive parameters and load conditions on switching dynamic and EMI characteristics. These influences are further analyzed based on experimental results and theoretical analysis of the switching transient processes. Finally, the study identifies factors limiting switching speed improvements in SiC modules, including voltage and current overshoots, gate voltage oscillations, and EMI, offering valuable insights for improving device performance.