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Low-Power-Operating 3C-SiC Ultraviolet Photodetector fora?￡Elevated Temperature Applications
摘要： This work demonstrates the systematic investigation of the effects of high temperature on key performance parameters including speed, sensitivity, stability, and repeatability of a 3C-SiC/Si ultraviolet (UV) photodetector (PD) at various operating temperatures ranging from 50°C to 200°C. The device with very low dark current (≈ 0.08 pA) exhibited high sensitivity of 4466 and fast rise and decay times of 0.34 s and 0.30 s at 50°C to exposure of 254 nm UV light at a bias voltage of 20 V. Additionally, the device showed very good performance at a low operating voltage of 0.5 V and high temperature of 200°C, with a rise time of 2.68 s and decay time of 1.44 s, while maintaining good stability and repeatability. The slight decrease in performance (sensitivity from 4466 to 932) at 200°C was attributed to the increase in lattice scattering at elevated temperatures, leading to a decrease in carrier mobility. Moreover, the device was fabricated using a very cost-effective process flow. Consequently, this study can contribute to the development of low-power, fast, highly sensitive, and cost-effective 3C-SiC UVPDs for use in high-temperature photonic applications.
关键词： fast response,high sensitivity,High-temperature UVPD,low-voltage operation,3C-SiC
更新于2025-09-23 15:21:01
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Laser-induced growth of large-area epitaxial graphene with low sheet resistance on 4H-SiC(0001)
摘要： Multilayer graphene on SiC is a promising material due to its compatibility with modern electronics technology. Herein, we demonstrate the growth of large-area (~10 × 5 mm2), high-quality (D/G area ratio: ~0.03) epitaxial graphene on 4H-SiC(0001) using a high-power continuous laser with an extremely fast heating rate of 500 °C/s. As the growth temperature rises from 1550 °C to 1780 °C, the number of graphene layers increases from three to more than ten. The obtained graphene/SiC samples are highly conductive, with a sheet resistance of as low as ~0.43 Ω/sq. The high power and fast heating rate of the laser contribute to the formation of large-area and low-sheet-resistance graphene. The high conductivity makes graphene/SiC a very promising material for applications in conductive films. The growth mechanism of graphene and the influence of the structural properties of graphene on the conductivity are also discussed.
关键词： Sheet resistance,Large-area,4H-SiC,Continuous laser,Epitaxial graphene
更新于2025-09-23 15:21:01
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Photovoltaic-Driven SiC MOSFET Circuit Breaker with Latching and Current Limiting Capability
摘要： This paper introduces a Solid State Circuit Breaker with Latching and Current Limiting capabilities for DC distribution systems. The proposed circuit uses very few electronic parts and it is fully analog. A SiC N-MOSFET driven by a photovoltaic driver and a maximum current detector circuit are the core elements of the system. This work details circuit operation under different conditions and includes experimental validation at 1 kVdc. Wide versatility, highly configurable, and very fast response, less than 1 μs in the case of short-circuit, are the most remarkable outcomes.
关键词： SiC MOSFET,Solid State Circuit Breaker (SSCB),fault current limiter,WBG semiconductors,DC power distribution
更新于2025-09-23 15:21:01
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-SiC
摘要： We investigate the quenching of the photoluminescence (PL) from the divacancy defect in 4H-SiC consisting of a nearest-neighbor silicon and carbon vacancies. The quenching occurs only when the PL is excited below certain photon energies (thresholds), which differ for the four different inequivalent divacancy configurations in 4H-SiC. An accurate theoretical ab initio calculation for the charge-transfer levels of the divacancy shows very good agreement between the position of the (0/?) level with respect to the conduction band for each divacancy configuration and the corresponding experimentally observed threshold, allowing us to associate the PL decay with conversion of the divacancy from neutral to negative charge state due to capture of electrons photoionized from other defects (traps) by the excitation. Electron paramagnetic resonance measurements are conducted in the dark and under excitation similar to that used in the PL experiments and shed light on the possible origin of traps in the different samples. A simple model built on this concept agrees well with the experimentally observed decay curves.
关键词： quenching,electron paramagnetic resonance,4H-SiC,divacancy,charge-transfer levels,photoluminescence
更新于2025-09-23 15:21:01
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Effects of CF<sub>4</sub> Surface Etching on 4H-SiC MOS Capacitors
摘要： Effects of CF4 etching on 4H-SiC MOS capacitor were investigated. Fluorine atoms were introduced to surface of 4H-SiC using CF4 dry etching process as a surface treatment, and 4H-SiC MOS capacitors with dry-oxide were fabricated with this treatment. As a result, the breakdown electric field of the MOS capacitors was increased and variation of the characteristics became lower than that of MOS capacitor without this treatment.
关键词： MOS Capacitor,Oxide/4H-SiC Interface,Dry Etching,Fluorine
更新于2025-09-23 15:21:01
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Use of 1.7 kV and 3.3 kV SiC Diodes in Si-IGBT/ SiC Hybrid Technology
摘要： Replacing conventional Si diodes with SiC diodes in Si insulated gate bipolar transistor (IGBT) modules is advantageous as it can reduce power losses significantly. Also, the fast switching nature of the SiC diode will allow Si IGBTs to operate at their full high-switching-speed potential, which at present conventional Si diodes cannot do. In this work, the electrical test results for Si-IGBT/4H-SiC-Schottky hybrid substrates (hybrid SiC substrates) are presented. These substrates are built for two voltage ratings, 1.7 kV and 3.3 kV. Comparisons of the 1.7 kV and the 3.3 kV Si-IGBT/Si-diode substrates (Si substrates) at room temperature (20 ?C, RT) and high temperature (125 ?C, HT) have shown that the switching losses in hybrid SiC substrates are miniscule as compared to those in Si substrates but necessary steps are required to mitigate the ringing observed in the current waveforms. Also, the effect of design variations on the electrical performance of 1.7 kV, 50 A diodes is reported here. These variations are made in the active and termination regions of the device.
关键词： Hybrid substrates,Switching losses,IGBT,JTE and FLRs,Schottky diode,SiC
更新于2025-09-23 15:21:01
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Effects of Parasitic Region in SiC Bipolar Junction Transistors on Forced Current Gain
摘要： Effects of a parasitic region in SiC BJTs on conductivity modulation and a forced current gain (????) were investigated by using TCAD simulation with various device structures. By introducing an Al+-implanted region below the base parasitic region, ???? can be improved because the implanted region can reduce the base spreading resistance, leading to alleviation of debiasing effect. ???? in devices with various parasitic areas, whose base spreading resistances were reduced by the Al+-implantation, were compared. We found that ???? can be enhanced by expanding the parasitic area if the base spreading resistance is sufficiently reduced. The higher ???? is attributed to an expanded conductivity-modulated region. The collector current spreading in the collector layer and hole injection from the parasitic region as well as from the intrinsic region can play a role to evoke conductivity modulation. Thus, the larger parasitic region can expand the conductivity-modulated region, which results in expansion of an active area and the enhancement of ????, though a higher base voltage is required.
关键词： forced current gain,conductivity modulation,parasitic region,hole injection,SiC BJT,base spreading resistance
更新于2025-09-23 15:21:01
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Laser-generated ns plasma pulses characterized using SiC Schottky diode
摘要： The nonequilibrium plasma generated by nanosecond laser pulse is characterized using a SiC detector connected in time-of-flight configuration to measure the radiations emitted from the plasma. Different metallic targets were irradiated by the pulsed laser at an intensity of 1010 W/cm2 and 200 mJ pulse energy. The SiC allows detecting ultraviolet radiations and soft X-rays, electrons, and ions. The obtained plasma has a temperature of the order of tens to hundreds eV depending on the atomic number of the irradiated target and ion accelerations of the order of 100 eV per charge state.
关键词： SiC-TOF,SiC detector,Laser-generated plasma,Photopeak
更新于2025-09-23 15:19:57
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Selective area laser-assisted doping of SiC thin films and blue light electroluminescence
摘要： Laser-assisted doping combined with annealing technique is used in selective areas to form a p–n junction on a SiC thin film grown by the pulsed laser deposition on a Si substrate at a temperature of 800 °C. This approach in an aluminum chloride solution and a phosphoric solution has resulted in p-SiC/n-Si and n-SiC/p-Si hetero-structures, respectively. Further, a functional in-plane p–n junction is realized side-by-side on the post-deposited SiC thin film. I–V characteristics by two probe technique showed the p–n diode characteristics. Blue light (400 nm) electroluminescence from the p–n junction on SiC thin film was observed in the forward biased condition. Further, an improvement in the I–V reverse characteristics was observed by illuminating the p–n SiC thin film with green/blue light.
关键词： pulsed laser deposition,laser assisted doping,SiC thin film,electroluminescence,silicon carbide,selective area doping
更新于2025-09-23 15:19:57
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Valley polarization reversal and spin ferromagnetism and antiferromagnetism in quantum dots of the topological insulator monolayer bismuthene on SiC
摘要： The valley and spin polarizations associated with electronic transport in quantum dots of the large-gap topological insulator (TI) monolayer bismuthene on SiC are investigated in the linear response regime using a minimal tight-binding model that accurately describes the low-energy electronic band structure of this TI. It is found that for zigzag edges the electronic edge states are strongly valley polarized if the Fermi energy lies in the bulk energy band gap. We predict the edge-state valley polarizations to switch between valleys K and K (cid:2) as the Fermi energy varies from the top of the valence band to the bottom of the conduction band or if the direction of electric current through the dot is reversed. If the electrostatic potential in the dot is nonuniform, we predict that the valley polarization of an electron can reverse as it travels through the dot. The valley polarization reversal is due to the zigzag edge-state dispersion crossing the center of the Brillouin zone that separates valleys K and K (cid:2) and is therefore predicted to be a general phenomenon. Although the spin polarization within the edge states is ferromagnetic, as expected for spin Hall devices, our calculations reveal the out-of-plane component of the spin polarization of the bulk valence band scattering states to be antiferromagnetic, and the direction of the out-of-plane component of the Neel vector to depend on whether the electronic accumulation belongs primarily to valley K or K (cid:2).
关键词： quantum dots,ferromagnetism,bismuthene,topological insulator,spin polarization,antiferromagnetism,SiC,tight-binding model,valley polarization
更新于2025-09-23 15:19:57