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Showing papers on "Silicon carbide published in 2021"


Journal ArticleDOI
TL;DR: In this paper, a membrane distributed reflector laser on a low-refractive-index and high-thermal-conductivity silicon carbide substrate was proposed to achieve a 42 GHz relaxation oscillation frequency.
Abstract: Increasing the modulation speed of semiconductor lasers has attracted much attention from the viewpoint of both physics and the applications of lasers. Here we propose a membrane distributed reflector laser on a low-refractive-index and high-thermal-conductivity silicon carbide substrate that overcomes the modulation bandwidth limit. The laser features a high modulation efficiency because of its large optical confinement in the active region and small differential gain reduction at a high injection current density. We achieve a 42 GHz relaxation oscillation frequency by using a laser with a 50-μm-long active region. The cavity, designed to have a short photon lifetime, suppresses the damping effect while keeping the threshold carrier density low, resulting in a 60 GHz intrinsic 3 dB bandwidth (f3dB). By employing the photon–photon resonance at 95 GHz due to optical feedback from an integrated output waveguide, we achieve an f3dB of 108 GHz and demonstrate 256 Gbit s−1 four-level pulse-amplitude modulations with a 475 fJ bit−1 energy cost of the direct-current electrical input. Directly modulated membrane distributed reflector lasers are fabricated on a silicon carbide platform. The 3 dB bandwidth, four-level pulse-amplitude modulation speed and operating energy for transmitting one bit are 108 GHz, 256 Gbit s−1 and 475 fJ, respectively.

99 citations


Journal ArticleDOI
TL;DR: In this article, the authors present a thorough review of development of SiC IGBT in the past 30 years and summarize the progresses of models, structure design, and performance in SiC ICIGBT.
Abstract: Along with the increasing maturity for the material and process of the wide bandgap semiconductor silicon carbide (SiC), the insulated gate bipolar transistor (IGBT) representing the top level of power devices could be fabricated by SiC successfully This article presents a thorough review of development of SiC IGBT in the past 30 years The progresses of models, structure design, and performance in SiC IGBT are summarized The challenges resulting from fabrication process and switching characteristics are discussed and analyzed in detail The experimental results and existing problems in SiC IGBT-based applications are summarized in the end

75 citations


Journal ArticleDOI
TL;DR: In this paper, a detailed review of the measures to modify the high-temperature mechanical properties of silicon carbide ceramic matrix composites (SiC CMCs) is presented.
Abstract: This article is a detailed review of the measures to modify the high-temperature mechanical properties of silicon carbide ceramic matrix composites (SiC CMCs), namely toughness, high-temperature stability and wear resistance Additionally, it briefly describes the common processing methods of the SiC CMCs and their application in the high-temperature field of aerospace The advantages and disadvantages of various existing processing and molding methods for the SiC CMCs are also discussed The high-temperature mechanical properties of the SiC CMCs are mainly affected by the properties of the matrix, added phase and interface It is crucial to reduce the crystal defects of the matrix and select a suitable enhancement phase for an elevated performance Moreover, it is important to improve the bonding at the interface between the enhancement phase and the matrix This review is expected to provide useful information for the subsequent development of complex SiC CMCs for high-temperature applications

74 citations


Journal ArticleDOI
TL;DR: In this paper, the use of silicon carbide (SiC) for direct detection of sub-GeV dark matter was proposed, which has properties similar to both silicon and diamond but has two key advantages: (i) it is a polar semiconductor which allows sensitivity to a broader range of dark matter candidates; and (ii) it exists in many stable polymorphs with varying physical properties and hence has tunable sensitivity to various dark matter models.
Abstract: We propose the use of silicon carbide (SiC) for direct detection of sub-GeV dark matter. SiC has properties similar to both silicon and diamond but has two key advantages: (i) it is a polar semiconductor which allows sensitivity to a broader range of dark matter candidates; and (ii) it exists in many stable polymorphs with varying physical properties and hence has tunable sensitivity to various dark matter models. We show that SiC is an excellent target to search for electron, nuclear and phonon excitations from scattering of dark matter down to 10 keV in mass, as well as for absorption processes of dark matter down to 10 meV in mass. Combined with its widespread use as an alternative to silicon in other detector technologies and its availability compared to diamond, our results demonstrate that SiC holds much promise as a novel dark matter detector.

70 citations


Journal ArticleDOI
TL;DR: In this article, a study involves fabrication of aluminium silicon carbide with muscovite/hydrated aluminium potassium silicate/aluminosilicate in stir casting method to obtain a hybrid metal matrix composite.
Abstract: The wide range of aluminium variants (alloys and composites) has made it an important material for aviation, automotive components, auto-transmission locomotive section units, SCUBA tanks, ship, vessels, submarines fabrication and design etc regardless of the fact that the aluminium alloys were being utilized in myriads of sectors owing to its exceptional superior and versatile functional characteristics, the property such as wear-resistant ought to be enhanced in order to further prolong diverse spectrum of applications An aluminium alloy having lower hardness and tensile strength has been incorporated with silicon carbide that drastically strengthens the properties This study involves fabrication of aluminium silicon carbide with muscovite/hydrated aluminium potassium silicate/aluminosilicate in stir casting method to obtain a hybrid metal matrix composite Maintaining a constant amount of aluminium and silicon carbide, muscovite or hydrated aluminium potassium silicate is varied to obtain three distinctive compositions of (Al/SiC/muscovite) composites The mechanical characteristics like tensile-strength, flexural-strength, toughness, hardness, scratch adhesion, percent-porosity and density were studied The dispersion of muscovite and silicon carbide particles were observed by viewing the microstructure photographs obtained using optical microscopy and Scanning Electron Microscope (SEM) EDAX analysis affirms the presence of reinforcing constituents in Al–Mg–Si–T6 alloy matrix A drum type wear apparatus was utilized to evaluate the percentage of wear-loss in different compositions using different loads and it was found that the wear-loss decreases linearly as the muscovite percentage was increased

68 citations


Journal ArticleDOI
TL;DR: In this paper, a kind of ZrO2-SiC/SiO2 fiber felt was prepared by combining chemical vapor infiltration (CVI) and oxidation treatment, and the SiO2 covered on SiC surface in the oxidation process, forming the unique sheath-core structure.

68 citations


Journal ArticleDOI
TL;DR: Kohler et al. as mentioned in this paper proposed a passivating contact based on a double layer of nanocrystalline silicon carbide that overcomes the trade-offs of conductivity, defect passivation and optical transparency.
Abstract: A highly transparent passivating contact (TPC) as front contact for crystalline silicon (c-Si) solar cells could in principle combine high conductivity, excellent surface passivation and high optical transparency. However, the simultaneous optimization of these features remains challenging. Here, we present a TPC consisting of a silicon-oxide tunnel layer followed by two layers of hydrogenated nanocrystalline silicon carbide (nc-SiC:H(n)) deposited at different temperatures and a sputtered indium tin oxide (ITO) layer (c-Si(n)/SiO2/nc-SiC:H(n)/ITO). While the wide band gap of nc-SiC:H(n) ensures high optical transparency, the double layer design enables good passivation and high conductivity translating into an improved short-circuit current density (40.87 mA cm−2), fill factor (80.9%) and efficiency of 23.99 ± 0.29% (certified). Additionally, this contact avoids the need for additional hydrogenation or high-temperature postdeposition annealing steps. We investigate the passivation mechanism and working principle of the TPC and provide a loss analysis based on numerical simulations outlining pathways towards conversion efficiencies of 26%. Passivating contacts hold promise for silicon solar cells yet the simultaneous optimization of conductivity, defect passivation and optical transparency remains challenging. Now Kohler et al. devise a passivating contact based on a double layer of nanocrystalline silicon carbide that overcomes these trade-offs.

65 citations


Journal ArticleDOI
01 Mar 2021
TL;DR: In this paper, a review of powder bed selective laser processing is presented, focusing on the process description, feedstock criteria and process parameters and strategy, and technical aspects and challenges about how to address these issues are presented.
Abstract: This review offers an overview on the latest advances in the powder bed selective laser processing, known as selective laser sintering/melting, of calcium phosphate, silicon carbide, zirconia, alumina, and some of their composites. A number of published studies between 1991 and August 2020 was collected, analyzed and an inclusive state of the art was created for this review. The paper focuses on the process description, feedstock criteria and process parameters and strategy. A comparison is made between direct and indirect powder bed selective laser processing of each ceramic, regarding the present achievements, limitations and solutions. In addition, technical aspects and challenges about how to address these issues are presented.

56 citations


Journal ArticleDOI
TL;DR: In this article, a comprehensive overview of the introduction to ceramic materials, its classifications, properties of ceramics and 3D-printed composite ceramic materials followed by state-of-the-art of silicon carbide along with their structure, its polytypes, properties and defects in SiC.
Abstract: Silicon carbide (SiC) is recognized as a notable semiconductor because of its outstanding characteristics, for instance wide-bandgap, outstanding magnetic properties, extraordinary chemical inertness, high thermal, mechanical, optical and electronic properties, generally utilized in solid-state lighting and power electronics because of its insufficient inherent carrier and high thermal conductivity under high-power/high-temperature/high-voltage or other such harsh environments. In the present review the authors discuss SiC and their physico-chemical properties as a new generation SiC functional materials and ceramic matrix composites with the primary purpose of improving their wide range of recent applications. However, it is to be noted that the biocompatibility and other such recent applications of SiC have been seldom understood by the researchers in spite of the fact that there is an ample scope for such studies on SiC. In the present review, the authors focus on the comprehensive overview of the introduction to ceramic materials, its classifications, properties of ceramics and 3D-printed composite ceramic materials followed by state-of-art of silicon carbide along with their structure, its polytypes, properties and defects in SiC. Further multidisciplinary applications of SiC nanoarchitectures have been systematically summarized, including photocatalytic technology, membrane technology gas- chemical sensing, field emission transistors, nanoelectronics, medical implants, biosensing and so on. Finally, the future prospects and research directions of SiC nanoarchitectures are proposed.

51 citations


Journal ArticleDOI
TL;DR: In this article, a 15°Y-X LiNbO3/SiO2/SiC multilayered substrate was designed and fabricated to suppress spurious resonance due to Rayleigh-mode and transverse-mode responses, and one-port resonators with a clean spectrum, a high electromechanical coupling coefficient of 22.00%, and an admittance ratio (impedance ratio) over 65 dB were successfully implemented.
Abstract: The rapid development of the fifth-generation (5G) wireless system is driving strong demand for high-performance radio frequency filters. This work studies shear horizontal surface acoustic wave (SAW) devices using 15°-rotated $Y$ -cut $X$ -propagating (15°Y-X) LiNbO3/SiO2/SiC multilayered substrates. Single-crystalline 15°Y-X LiNbO3 films are bonded to SiO2/SiC handling substrates by the smart cut technology. On the basis of accurate finite-element-method simulations, LiNbO3/SiO2/SiC wafer configurations are optimized to suppress spurious resonance due to Rayleigh-mode and transverse-mode responses, and one-port resonators with a clean spectrum, a high electromechanical coupling coefficient of 22.00%, and an admittance ratio (impedance ratio) over 65 dB are successfully implemented. Based on the characteristics of the resonators, high-performance filters with a center frequency of 1.28 GHz, a large 3-dB fractional bandwidth of 16.65%, and a low minimum insertion loss of 1.02 dB are successfully designed and fabricated. Furthermore, no ripples in the passband of the filters are observed. Additionally, the filters exhibit a temperature coefficient of center frequency of −63.8 ppm/°C and a large power durability of 33.2 dBm. This work confirms the high performances of the SAW devices using the 15°Y-X LiNbO3/SiO2/SiC multilayered substrate, and this type of SAW device exhibits a prospect of commercial applications in the 5G wireless system.

50 citations


Journal ArticleDOI
22 Apr 2021
TL;DR: In this paper, the authors presented the application of wide bandgap (WBG) semiconductor devices with cryogenic cooling and demonstrated the feasibility of operating high-power SiC converter with Cryogenic cooling.
Abstract: This article presents the cryogenically cooled application for wide bandgap (WBG) semiconductor devices. Characteristics of silicon carbide (SiC) and gallium nitride (GaN) at cryogenic temperatures are illustrated. SiC MOSFETs exhibit increased on-state resistance and slower switching speed at cryogenic temperatures. However, cryogenic cooling provides low ambient temperature environment and thus enables the SiC converter to operate at lower junction temperature to achieve higher efficiency compared to room temperature cooling. A cryogenically cooled MW-level SiC inverter prototype is developed and demonstrated the feasibility of operating high-power SiC converter with cryogenic cooling. GaN HEMTs exhibit more than five times on-state resistance reduction and faster switching speed at cryogenic temperatures which makes GaN HEMTs an excellent candidate for cryogenic power electronics applications. The significantly reduced on-state resistance of GaN devices provides the possibility to operate them at a current level much higher than rated current at cryogenic temperatures. A GaN double pulse test (DPT) circuit is constructed and demonstrated that GaN HEMTs can operate at nearly four times of rated current at cryogenic temperatures. Challenges of utilizing WBG device with cryogenic cooling are discussed and summarized.

Journal ArticleDOI
01 May 2021-Silicon
TL;DR: In this paper, the effect of increase in an atoms numbers added to the (PVA-NiO-SiC) structures on the geometrical parameters, electronic and spectroscopic characteristics for low cost electronic applications by Gaussian 0.9 program with help of Gaussian View 0.5 using DFT with (LanL2DZ).
Abstract: This work aims to study of the effect of increase in an atoms numbers added to the (PVA-NiO-SiC) structures on the geometrical parameters, electronic and spectroscopic characteristics for low cost electronic applications by Gaussian 0.9 program with help of Gaussian View 0.5 using DFT with (LanL2DZ). The structural, electronic and optical properties included: energy gap, cohesive energy, chemical softness, electron affinity, ionization potential, chemical hardness, electronegativity, electrophilicity, density of states, IR spectra, UV spectra and Raman spectra. The results indicated to the increase in atoms numbers leads to decrease the cohesive energy, energy gap, and ionization potential. The UV-Vis spectra of small molecules are higher than larger molecules in intensity and moves toward cut off energy frequency for large molecules. The results indicated to the (PVA-NiO-SiC) structures can be useful for various optoelectronics fields like: electronic gates, diodes, photovoltaic devices, transistors...etc.

Journal ArticleDOI
TL;DR: In this paper, the state-of-the-art additive manufacturing technologies for the fabrication of relatively pure SiC, which show great potential to retain its strength under neutron irradiation, are discussed.

Journal ArticleDOI
TL;DR: In this article, a method to make liquid metal composites by vigorously mixing gallium (Ga) with non-metallic particles of graphene oxide (G-O), graphite, diamond, and silicon carbide that display either paste or putty-like behavior depending on the volume fraction is described.
Abstract: We report a versatile method to make liquid metal composites by vigorously mixing gallium (Ga) with non-metallic particles of graphene oxide (G-O), graphite, diamond, and silicon carbide that display either paste or putty-like behavior depending on the volume fraction. Unlike Ga, the putty-like mixtures can be kneaded and rolled on any surface without leaving residue. By changing temperature, these materials can be stiffened, softened, and, for the G-O-containing composite, even made porous. The gallium putty (GalP) containing reduced G-O (rG-O) has excellent electromagnetic interference shielding effectiveness. GalP with diamond filler has excellent thermal conductivity and heat transfer superior to a commercial liquid metal-based thermal paste. Composites can also be formed from eutectic alloys of Ga including Ga-In (EGaIn), Ga-Sn (EGaSn), and Ga-In-Sn (EGaInSn or Galinstan). The versatility of our approach allows a variety of fillers to be incorporated in liquid metals, potentially allowing filler-specific "fit for purpose" materials.

Journal ArticleDOI
TL;DR: In this article, the most commonly used ballistic ceramics (alumina, silicon carbide, and boron carbide) are compared via various performance mechanisms in a review.

Journal ArticleDOI
Chao Ding1, Heziqi Liu1, Khai D. T. Ngo1, Rolando Burgos1, Guo-Quan Lu1 
TL;DR: In this paper, a porous interposer made of low-temperature sintered silver is introduced to reduce the thermomechanical stresses in the power module and a double-side cooled half-bridge module consisting of two 1200 V, 149 A SiC MOSFETs was designed, fabricated, and characterized.
Abstract: Planar, double-side cooled power modules are emerging in electric-drive inverters because of their low profile, better heat extraction, and lower package parasitic inductances However, there is still a concern about their reliability due to the rigid interconnection between the device chips and two substrates of the power module In this article, a porous interposer made of low-temperature sintered silver is introduced to reduce the thermomechanical stresses in the module A double-side cooled half-bridge module consisting of two 1200 V, 149 A SiC MOSFETs was designed, fabricated, and characterized By using the sintered-Ag instead of solid copper interposers, our simulation results showed that, at a total power loss of 200 W, the thermomechanical stress at the most vulnerable interfaces (interposer-attach layer) was reduced by 42% and in the SiC MOSFET by 50% with a tradeoff of only 36% increase in junction temperature The sintered-Ag interposers were readily fabricated into the desired dimensions without postmachining and did not require any surface finishing for die bonding and substrate interconnection by silver sintering The porous interposers were also deformable under a low force or pressure, which helped to accommodate chip thickness and/or substrate-to-substrate gap variations in the planar module structure, thus simplifying module fabrication The experimental results on the electrical performance of the fabricated SiC modules validated the success of using the porous silver interposers for fabricating planar, double-side cooled power modules

Journal ArticleDOI
10 Feb 2021-ACS Nano
TL;DR: In this paper, a strengthened reduced graphene oxide (SrGO)-reinforced multi-interfacial carbon-silicon carbide (C-SiC)n matrix is reported, which is fabricated by depositing a carbon-strengthening layer into rGO foam followed by alternate filling of pyrocarbon and silicon carbide via a precursor infiltration pyrolysis (PIP) method.
Abstract: Materials with low density, exceptional thermal and corrosion resistance, and ultrahigh mechanical and electromagnetic interference (EMI) shielding performance are urgently demanded for aerospace and military industries. Efficient design of materials' components and microstructures is crucial yet remains highly challenging for achieving the above requirements. Herein, a strengthened reduced graphene oxide (SrGO)-reinforced multi-interfacial carbon-silicon carbide (C-SiC)n matrix (SrGO/(C-SiC)n) composite is reported, which is fabricated by depositing a carbon-strengthening layer into rGO foam followed by alternate filling of pyrocarbon (PyC) and silicon carbide (SiC) via a precursor infiltration pyrolysis (PIP) method. By increasing the number of alternate PIP sequences (n = 1, 3 and 12), the mechanical, electrical, and EMI shielding properties of SrGO/(C-SiC)n composites are significantly increased. The optimal composite exhibits excellent conductivity of 8.52 S·cm-1 and powerful average EMI shielding effectiveness (SE) of 70.2 dB over a broad bandwidth of 32 GHz, covering the entire X-, Ku-, K-, and Ka-bands. The excellent EMI SE benefits from the massive conduction loss in highly conductive SrGO skeletons and polarization relaxation of rich heterogeneous PyC/SiC interfaces. Our composite features low density down to 1.60 g·cm-3 and displays robust compressive properties (up to 163.8 MPa in strength), owing to the uniformly distributed heterogeneous interfaces capable of consuming great fracture energy upon loadings. Moreover, ultrahigh thermostructural stability (up to 2100 °C in Ar) and super corrosion resistance (no strength degradation after long-term acid and alkali immersion) are also discovered. These excellent comprehensive properties, along with ease of low-cost and scalable production, could potentially promote the practical applications of the SrGO/(C-SiC)n composite in the near future.

Journal ArticleDOI
TL;DR: In this paper, the authors provide a roadmap for potential applications and further development of silicon carbide membranes in the field of liquid filtration, and present a wide range of applications in water and wastewater treatment and other applications.

Journal ArticleDOI
TL;DR: In this article, the production of fiber-reinforced UHTC matrix composites (UHTCMCs) formed via the additive manufacturing technique of direct ink writing (DIW) is reported.
Abstract: Ultra-high temperature ceramics (UHTCs) are of interest for thermally- and/or mechanically- extreme environments because of their high melting temperatures (> 3000 °C) and ablation resistance. More widespread use is limited by low fracture toughness and inability to be processed into complex-shaped components. Here, we report the production of fiber-reinforced UHTC matrix composites (UHTCMCs) formed via the additive manufacturing technique of direct ink writing (DIW). Slurry 'inks' were developed containing up to 47.5 vol% of the UHTC zirconium diboride (ZrB2), up to 10 vol% chopped silicon carbide fiber (SiCf), and a silicon carbide (SiC) precursor polymer. Lattice structures and flexural specimens were printed and pyrolyzed to form UHTCMCs with aligned (relative to the print direction) SiCf in the ZrB2 – SiC matrix. Flexural strength of fiber-containing parts is presented, and fiber alignment due to deposition is analyzed with X-ray computed tomography. Defects that occurred during the DIW process, and their probable causes and mitigation strategies are also discussed.

Journal ArticleDOI
TL;DR: In this article, nano-sized silicon carbide (SiC: 0wt, 1wt, 2wt, 4wt, and 8wt) reinforced copper (Cu) matrix nanocomposites were manufactured, pressed, and sintered at 775 and 875°C in an argon atmosphere.
Abstract: Nano-sized silicon carbide (SiC: 0wt%, 1wt%, 2wt%, 4wt%, and 8wt%) reinforced copper (Cu) matrix nanocomposites were manufactured, pressed, and sintered at 775 and 875°C in an argon atmosphere. X-ray diffraction (XRD) and scanning electron microscopy were performed to characterize the microstructural evolution. The density, thermal expansion, mechanical, and electrical properties were studied. XRD analyses showed that with increasing SiC content, the microstrain and dislocation density increased, while the crystal size decreased. The coefficient of thermal expansion (CTE) of the nanocomposites was less than that of the Cu matrix. The improvement in the CTE with increasing sintering temperature may be because of densification of the microstructure. Moreover, the mechanical properties of these nanocomposites showed noticeable enhancements with the addition of SiC and sintering temperatures, where the microhardness and apparent strengthening efficiency of nanocomposites containing 8wt% SiC and sintered at 875°C were 958.7 MPa and 1.07 vol%-1, respectively. The electrical conductivity of the sample slightly decreased with additional SiC and increased with sintering temperature. The prepared Cu/SiC nanocomposites possessed good electrical conductivity, high thermal stability, and excellent mechanical properties.

Journal ArticleDOI
TL;DR: In this article, the effect of pH, persulfate concentration, and TiO2 dosage on CMP in-depth, and to ultimately optimize the polishing process was investigated for improving the CMP properties of Si-face of the 4H-SiC wafers.

Journal ArticleDOI
TL;DR: In this paper, the effects of grinding speed on the material removal mechanism of SiCf/SiC by single grain grinding were investigated and it was shown that increasing speed grinding could embrittle the material and enhance the breakage of fibers.

Journal ArticleDOI
TL;DR: In this article, an AZ61 magnesium alloy with reinforcement of boron carbide and silicon carbide in different percentage levels was used and a plate was formed through stir casting technique.
Abstract: Wire Cut Electric Discharge Machining (WCEDM) is a novel method for machining different materials with application of electrical energy by the movement of wire electrode. For this work, an AZ61 magnesium alloy with reinforcement of boron carbide and silicon carbide in different percentage levels was used and a plate was formed through stir casting technique. The process parameters of the stir casting process are namely reinforcement %, stirring speed, time of stirring, and process temperature. The specimens were removed from the casted AZ61 magnesium alloy composites through the Wire Cut Electric Discharge Machining (WCEDM) process, the material removal rate and surface roughness vales were carried out creatively. L 16 orthogonal array (OA) was used for this work to find the material removal rate (MRR) and surface roughness. The process parameters of WCEDM are pulse on time (105, 110, 115 and 120 µs), pulse off time (40, 50, 60 and 70 µs), wire feed rate (2, 4, 6 and 8 m/min), and current (3, 6, 9 and 12 Amps). Further, this study aimed to estimate the maximum ultimate tensile strength and micro hardness of the reinforced composites using the Taguchi route.

Journal ArticleDOI
TL;DR: The E-SiCure project as mentioned in this paper developed technologies to support the fabrication of radiation-hard silicon carbide detectors of special nuclear materials, and the main goal was the development of successful Schottky barrier based detectors and the identification of the main carrier life-time-limiting defects in the SiC active areas.
Abstract: In the last two decades we have assisted to a rush towards finding a 3He-replacing technology capable of detecting neutrons emitted from fissile isotopes. The demand stems from applications like nuclear war-head screening or preventing illicit traffic of radiological materials. Semiconductor detectors stand among the strongest contenders, particularly those based on materials possessing a wide band gap like silicon carbide (SiC). We review the workings of SiC-based neutron detectors, along with several issues related to material properties, device fabrication and testing. The paper summarizes the experimental and theoretical work carried out within the E-SiCure project (Engineering Silicon Carbide for Border and Port Security), co-funded by the NATO Science for Peace and Security Programme. The main goal was the development of technologies to support the fabrication of radiation-hard silicon carbide detectors of special nuclear materials. Among the achievements, we have the development of successful Schottky barrier based detectors and the identification of the main carrier life-time-limiting defects in the SiC active areas, either already present in pristine devices or introduced upon exposure to radiation fields. The physical processes involved in neutron detection are described. Material properties as well as issues related to epitaxial growth and device fabrication are addressed. The presence of defects in as-grown material, as well as those introduced by ionizing radiation are reported. We finally describe several experiments carried out at the Jozef Stefan Institute TRIGA Mark II reactor (Ljubljana, Slovenia), where a set of SiC-based neutron detectors were tested, some of which being equipped with a thermal neutron converter layer. We show that despite the existence of large room for improvement, Schottky barrier diodes based on state-of-the-art 4 H -SiC are closing the gap between gas- and semiconductor-based detectors regarding their sensitivity.

Journal ArticleDOI
TL;DR: In this article, a detailed comparison of SM topologies regarding their structural properties, design and control complexity, voltage capability, losses, and fault handling is given, and Alternatives to state-of-the-art SMs with Si insulated-gate bipolar transistors are proposed, and several promising design approaches are discussed.
Abstract: Recent advancements in silicon carbide (SiC) power semiconductor technology enable developments in the high-power sector, e.g., high-voltage-direct-current (HVdc) converters for transmission, where today silicon (Si) devices are state-of-the-art. New submodule (SM) topologies for modular multilevel converters offer benefits in combination with these new SiC semiconductors. This article reviews developments in both fields, SiC power semiconductor devices and SM topologies, and evaluates their combined performance in relation to core requirements for HVdc converters: grid code compliance, reliability, and cost. A detailed comparison of SM topologies regarding their structural properties, design and control complexity, voltage capability, losses, and fault handling is given. Alternatives to state-of-the-art SMs with Si insulated-gate bipolar transistors (IGBTs) are proposed, and several promising design approaches are discussed. Most advantages can be gained from three technology features. First, SM bipolar capability enables dc fault handling and reduced the energy storage requirements. Second, SM topologies with parallel conduction paths in combination with SiC metal–oxide–semiconductor field-effect transistors offer reduced losses. Third, a higher SM voltage enabled by a higher blocking voltage of SiC devices results in a reduced converter complexity. For the latter, ultrahigh-voltage bipolar devices, such as SiC IGBTs and SiC gate turn- off thyristors, are envisioned.

Journal ArticleDOI
TL;DR: In this article, a graphite-embedded insulated metal substrate (thermally-annealed-pyrolytic-graphite embeddings) was proposed for widebandgap power modules.
Abstract: Emerging wide-bandgap (WBG) semiconductor devices such as silicon carbide (SiC) metal–oxide semiconductor field-effect transistors (MOSFETs) and gallium nitride high-electron-mobility transistors can handle high power in reduced semiconductor areas better than conventional Si-based devices owing to superior material properties. With increased power loss density in a WBG-based converter and reduced die size in power modules, thermal management of power devices must be optimized for high performance. This article presents a graphite-embedded insulated metal substrate (thermally-annealed-pyrolytic-graphite-embedded insulated metal substrate—IMSwTPG) designed for WBG power modules. Theoretical thermal performance analysis of graphite-embedded metal cores is presented, with design details for IMSwTPG with embedded graphite to replace a direct-bonded copper (DBC) substrate. The proposed IMSwTPG is compared with an aluminum nitride-based DBC substrate using finite-element thermal analysis for steady-state and transient thermal performance. The solutions’ thermal performances are compared under different coolant temperature and thermal loading conditions, and the proposed substrate's electrical performance is validated with static and dynamic characterization. Using graphite-embedded substrates, junction-to-case thermal resistance of SiC MOSFETs can be reduced up to 17%, and device current density can be increased by 10%, regardless of the thermal management strategy used to cool the substrate. Reduced transient thermal impedance of up to 40% of dies owing to increased heat capacity is validated in transient thermal simulations and experiments. The half-bridge power module's electrical performance is evaluated for on -state resistance, switching performance, and switching loss at three junction temperature conditions. The proposed substrate solution has minimal impact on conduction and switching performance of SiC MOSFETs.

Journal ArticleDOI
01 Jun 2021
TL;DR: In this article, BAs and BP cooling substrates can be heterogeneously integrated with metals, a widebandgap semiconductor (gallium nitride, GaN) and high-electron-mobility transistor devices.
Abstract: Thermal management is critical in modern electronic systems. Efforts to improve heat dissipation have led to the exploration of novel semiconductor materials with high thermal conductivity, including boron arsenide (BAs) and boron phosphide (BP). However, the integration of such materials into devices and the measurement of their interface energy transport remain unexplored. Here, we show that BAs and BP cooling substrates can be heterogeneously integrated with metals, a wide-bandgap semiconductor (gallium nitride, GaN) and high-electron-mobility transistor devices. GaN-on-BAs structures exhibit a high thermal boundary conductance of 250 MW m−2 K−1, and comparison of device-level hot-spot temperatures with length-dependent scaling (from 100 μm to 100 nm) shows that the power cooling performance of BAs exceeds that of reported diamond devices. Furthermore, operating AlGaN/GaN high-electron-mobility transistors with BAs cooling substrates exhibit substantially lower hot-spot temperatures than diamond and silicon carbide at the same transistor power density, illustrating their potential for use in the thermal management of radiofrequency electronics. We attribute the high thermal management performance of BAs and BP to their unique phonon band structures and interface matching. Boron arsenide and boron phosphide cooling substrates can be integrated with other materials, including the wide-bandgap semiconductor gallium nitride, creating structures that exhibit high thermal boundary conductances and high-electron-mobility transistors that exhibit low hot-spot temperatures.

Journal ArticleDOI
Baojie Zhang1, Zongwei Tong1, Huijun Yu1, Hui Xu1, Zhiwei Chen1, Xiaolei Li1, Huiming Ji1 
TL;DR: In this paper, a novel ZrO2/SiC-based nanofiber membranes with high temperature resistance and low thermal conductivity were prepared for the first time using simple blending method via electrospinning technique combined with subsequent curing and pyrolysis.

Journal ArticleDOI
TL;DR: In this paper, the effects of the sintering pressure, temperature and holding time on the mechanical properties of 50-vol% silicon carbide particle (SiCp)/2024Al composites prepared by SPS were investigated.