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oe1(光电查) - 科学论文

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出版时间
  • 2018
研究主题
  • gate oxide integrity
  • avalanche ruggedness
  • SiC MOSFET
  • bias temperature instability
应用领域
  • Electronic Science and Technology
机构单位
189 条数据
?? 中文（中国） ▾

  • Physical nature of electrically detected magnetic resonance through spin dependent trap assisted tunneling in insulators

    摘要： We show that electrically detected magnetic resonance (EDMR), through spin dependent trap assisted tunneling (SDTT) in amorphous SiC, exhibits approximately equal amplitudes at very high (8.5 T) and very low (0.013 T) magnetic fields at room temperature. This result strongly supports an SDTT/EDMR model in which spins at two nearby sites involved in a tunneling event are coupled for a finite time in circumstances somewhat analogous to spin pair coupling in the spin dependent recombination/EDMR model of Kaplan, Solomon, and Mott (KSM) [Kaplan, Solomon, and Mott, J. Phys. Lett. 39, 51 (1978)]. Since a comparable near zero magnetic field change in resistance is also observed in these samples, our results support the idea that this magnetoresistance response is also the result of a KSM-like mechanism involving SDTT. Additionally, we observe a large enhancement in SDTT/EDMR at high field (8.5 T) for temperatures below 50 K, which suggests the potential utility of SDTT in spin based quantum computation and other spintronic applications.

    关键词： spin dependent trap assisted tunneling,electrically detected magnetic resonance,spintronics,amorphous SiC,magnetoresistance

    更新于2025-09-04 15:30:14

  • [IEEE 2018 IEEE 18th International Power Electronics and Motion Control Conference (PEMC) - Budapest, Hungary (2018.8.26-2018.8.30)] 2018 IEEE 18th International Power Electronics and Motion Control Conference (PEMC) - Impact of the Different Parasitic Inductances on the Switching Behavior of SiC MOSFETs

    摘要： This paper experimentally investigates into the effects of parasitic inductances on the switching performance of a SiC MOSFET halfbridge. As the switching dynamics of wide-bandgap power semiconductors are by magnitudes larger compared to silicon devices, the parasitic elements in the switching cell become increasingly important, as they limit the current and voltage slopes and cause oscillations. A thorough understanding of those effects is necessary for the design of highly efficient and integrated next-generation power electronic converters. An implementation method to realize cheap and well-reproducible variable inductors in the nanohenry range is presented. Furthermore, a test PCB equipped with SiC MOSFETs is built and double pulse experiments are carried out under the variation of all relevant inductances in the switching cell. The results are analyzed with respect to the switching performance and differences between the switching transients of Si and SiC devices are demonstrated and explained with respect to the parasitic elements.

    关键词： switching performance,power electronics,parasitic inductances,double pulse experiments,SiC MOSFET

    更新于2025-09-04 15:30:14

  • [IEEE 2017 14th IEEE India Council International Conference (INDICON) - Roorkee (2017.12.15-2017.12.17)] 2017 14th IEEE India Council International Conference (INDICON) - Extraction and de-embedding of S-parameters using small-signal modeling for AlGaN/GaN HEMTs

    摘要： At high frequency, various structures such as probe, pads and the parameter measurement of HEMT device. To precisely measure the device intrinsic performance, it is required to de-embed these parasitic effects. In this paper, only two structures based de-embedding procedure is used to reach to the device plane. This paper shows difference between measured and extracted S-parameters based on Berroth and Meras model, with de-embedding and without de-embedding. In this paper we use fabricated AlGaN/GaN HEMT on SiC transistor of 0.8(cid:117) 100 μm2 as reference device. Open and short structures fabricated and measured on the same substrate are used in this extraction procedure. Magnitude and phase comparison are also explained.

    关键词： Two step de-embedding,HEMT,SiC substrate,GaN,open and short

    更新于2025-09-04 15:30:14

  • Improved turn-on characteristics of 4H SiC asymmetrical thyristor with double epitaxial n-base

    摘要： A new 4H-SiC asymmetrical thyristor with double epitaxial n-base is proposed and evaluated by the two-dimensional numerical simulations. It features a high-low doping profile to modify the electric field of the thin n-base in vertical direction. The built-in electric field enhances the injected minority carriers flow through the n-base as fast as possible and reducing the combination in n-base. As a result, the current gain of the upper p-n-p transistor in 4H-SiC thyristor is promoted. Compared to the conventional thyristor, the turn-on characteristics of the new structure are improved significantly. Simulation results indicate that the turn-on time of the new thyristor is reduced from 317ns that in conventional 6500V 4H-SiC thyristor to 96ns, under the load current of 180A/cm2 and bus voltage of 800V.

    关键词： Turn-on time,Thyristors,4H-SiC

    更新于2025-09-04 15:30:14

  • Conduction mechanisms of the reverse leakage current of 4H-SiC Schottky barrier diode

    摘要： A new numerical method for determining the reverse transition voltage between thermionic and tunneling mechanisms has been performed for 4H-SiC Schottky barrier diode. The idea of this method is based on equality between thermionic emission and tunneling process and both of them are combined with barrier lowering model. Application of this method shows a strong discrepancy between our results and that deduced from Padovani-Stratton condition. The reverse transition voltage was found increase linearly with increasing the barrier height, the effective mass and the inverse of doping concentration. In order to predict the reverse transition voltage as a function of temperature, doping concentration and barrier height for 4H-SiC Schottky barrier diode an analytical model has been proposed.

    关键词： image force barrier lowering,reverse transition voltage,SiC Schottky diode,thermionic emission,tunneling current

    更新于2025-09-04 15:30:14

  • [IEEE 2018 14th IEEE International Conference on Solid-State and Integrated Circuit Technology (ICSICT) - Qingdao, China (2018.10.31-2018.11.3)] 2018 14th IEEE International Conference on Solid-State and Integrated Circuit Technology (ICSICT) - Simulation of a Novel Integrated 4H-SiC Temperature Sensor

    摘要： This paper presents a novel integrated Schottky barrier diode temperature sensor in a 4H-SiC power MOSFET. Dual electrical isolation and additional current path are applied to this temperature sensor, allowing the sensor to work properly in any operating state of power MOSFET. Due to the sufficient electrical isolation, the crosstalk between sensor and power MOSFET is almost eliminated. Furthermore, high sensitivity S=1.21mV/K is observed for a constant bias current of Id=1mA. The temperature sensor exhibits a good degree of linearity with a root mean square error R2=0.99996.

    关键词： Temperature sensor,4H-SiC,Power MOSFET,Self-heating,Crosstalk

    更新于2025-09-04 15:30:14

  • -SiC

    摘要： Optical charge state switching was previously observed in photoluminescence experiments for the divacancy defect in 4H-SiC. The participating dark charge state could not be identified with certainty. We use constrained density-functional theory to investigate the mechanism of charge state conversion from the bright neutral charge state of the divacancy defect to the positive and negative charge states including corresponding recovery of the neutral charge state. While we can confirm that the positive charge state is dark, we do not find evidence that the negative charge state is dark. We compute similar absorption energies required for conversion of the neutral defect to both charge states. However, the formation of the positive charge state requires a series of excitations involving a 2-photon excitation, while the creation of the negative charge state is achieved through a single 2-photon process. Calculated absorption energies for the recovery of the neutral defect from the positive charge state fit the experimental value better than those from the negative charge state. Defect formation energies as a function of the Fermi energy show a very small Fermi energy range in which the negative charge state is most stable, while the positive charge state exhibits a wide stability range. Overall, our computational results give more support to the identification of the dark charge state as the positive over the negative charge state in the mechanism of optical charge state switching.

    关键词： divacancy defect,optical charge state switching,constrained density-functional theory,photoluminescence,4H-SiC

    更新于2025-09-04 15:30:14

  • Effect of Ti addition on the wetting and brazing of Sn0.3Ag0.7Cu filler on SiC ceramic

    摘要： The wetting behavior of Sn0.3Ag0.7Cu (SAC) filler with the addition of Ti on SiC ceramic was investigated using sessile drop method. SiC/SiC was brazed by SAC-Ti filler with different Ti content at 1223 K (950 °C) for 10 minutes. The wettability of SAC-Ti filler on SiC was significantly enhanced with the addition of Ti. The contact angle decreased at first and then increased with increasing Ti content. The lowest contact angle of 9° was obtained with SAC-1.5Ti (wt.%) filler. When Ti content further increased to 2.0 wt.%, the contact angle increased, due to the intense reaction of Ti-Sn. The reaction between Ti and SiC controlled the wetting behavior of SAC-Ti on the SiC substrate and the reaction products such as TiC and Ti5Si3 were formed. The wetting of SAC-Ti on SiC was reaction-controlled. Interfacial reaction products TiC and Ti5Si3 were observed. The wetting activation energy in spreading stage was calculated to be 129.3 kJ/mol. Completely filled SiC/SiC joints were obtained using the filler with Ti content higher than 0.5 wt.%. The fillet height increased firstly then decreased with mounting Ti content. The shear strength of joints increased first with the addition of Ti then decreased with Ti content increasing to 2.0 wt.%. The highest shear strength of 35.7 MPa was obtained with SAC-1.5 Ti (wt.%) filler.

    关键词： wetting,brazing,Ti addition,Sn0.3Ag0.7Cu,SiC ceramic

    更新于2025-09-04 15:30:14

  • [ASME ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems - San Francisco, California, USA (Monday 27 August 2018)] ASME 2018 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems - Failure Mechanism Assessment of TO-247 Packaged SiC Power Devices

    摘要： As the efficiency of power electronics becomes more important, the use of silicon carbide (SiC) devices in power electronics has shown several benefits in efficiency, blocking voltage and high temperature operation. In addition, the ability of SiC to operate at higher frequencies due to lower switching losses can result in reduced weight and volume of the system, which also are important factors in vehicles. However, the reliability of packaged SiC devices is not yet fully assessed. Previous work has predicted that the different material properties of SiC compared to Si could have a large influence on the failure mechanisms and reliability. For example, the much higher elastic modulus of SiC compared to Si could increase strain on neighboring materials during power cycling. In this work, the failure mechanisms of packaged Si- and SiC-based power devices have been investigated following power cycling tests. The packaged devices were actively cycled in 4.5 s heating and 20 s cooling at ΔT = 60 - 80 K. A failure analysis using micro-focus X-ray and scanning acoustic microscopy (SAM) was carried out in order to determine the most important failure mechanisms. The results of the analysis indicate that the dominant failure mechanism is wire bond lift-off at the device chip for all of the SiC-based devices. Further analysis is required to determine the exact failure mechanisms of the analyzed Si-based devices. In addition, the SiC-based devices failed before the Si-based devices, which could be a result of the different properties of the SiC material.

    关键词： power cycling,SiC,power electronics,failure mechanisms,reliability

    更新于2025-09-04 15:30:14

  • Synthesis and characterization of carbon-poor SiC nanowires via vapor-liquid-solid growth mechanism

    摘要： Nanowires growth via vapor-liquid-solid mechanism leads to high-quality SiC nanowires. C content is key issue affecting the morphology and composition of SiC nanowires. Here, we report the synthesis and growth mechanism of 3C-SiC nanowires containing reduced amount of C, which are grown on single-crystal Si via pyrolysis of polycarbosilane (PCS) by adjusting pyrolysis temperature and precursor. SiC nanowires have a diameter of 50 nm, while their thickness is 43.75 μm. High-temperature stability of precursors with multiple side-chain groups has an impact on the reaction rate, in result the solid precursor state and pyrolysis temperature at 1350°C are beneficial to the formation of pure carbon-poor SiC nanowires.

    关键词： precursor state,vapor-liquid-solid growth mechanism,SiC nanowires,pyrolysis temperature

    更新于2025-09-04 15:30:14