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Residual strain in an epilayer grown on a foreign wafer induces epiwafer's bow, that is often considered undesirable. Wafer bow however, can be advantageous because both the direction and magnitude of strain are vital for the fabrication of various Micro Electro Mechanical Systems (MEMS), such as resonators. Here strain control is reported for highly mismatched heteroepitaxy of cubic silicon carbide (3C–SiC) compound semiconductor on silicon (Si), a prized functional material, dependent solely on carbon to silicon ratio (C/Si) during growth. While Si–rich condition enhances growth and generates positive curvature i.e. tensile strain, C–rich condition suppresses growth and produces negative curvature i.e. compressive strain. An optimum region emerges with virtually no strain and superior crystallinity. Our findings are significant for the knowledge of heteroepitaxy of 3C–SiC and may be broadened to heteroepitaxy of other compound semiconductors. [ABSTRACT FROM AUTHOR]

Abstract Residual strain in an epilayer grown on a foreign wafer induces epiwafer’s bow, that is often considered undesirable. Wafer bow however, can be advantageous because both the direction and magnitude of strain are vital for the fabrication of various Micro Electro Mechanical Systems (MEMS), such as resonators. Here strain control is reported for highly mismatched heteroepitaxy of cubic silicon carbide (3C–SiC) compound semiconductor on silicon (Si), a prized functional material, dependent solely on carbon to silicon ratio (C/Si) during growth. While Si–rich condition enhances growth and generates positive curvature i.e. tensile strain, C–rich condition suppresses growth and produces negative curvature i.e. compressive strain. An optimum region emerges with virtually no strain and superior crystallinity. Our findings are significant for the knowledge of heteroepitaxy of 3C–SiC and may be broadened to heteroepitaxy of other compound semiconductors.

Investigation of surface blistering and exfoliation in silicon carbide (SiC) by H+ ion irradiation can be utilized for the smart cut or ion cut process, which will overcome the major challenges impeding the technological development of SiC. Blister formation and exfoliation in cubic 3CSiC were studied by carrying out 50 keV H+ ion irradiations. Both formation and exfoliation of blisters were observed in post-annealed (at 600 °C and 800 °C) samples (ion fluence: 7 × 1016 ions/cm2), where the disorder level is 0.95, which is close to the amorphization dose. The samples were characterized using optical microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and Raman scattering techniques. AFM measurements indicate that blisters exfoliate at a depth of around 289 nm, where H ions result in maximum damage. Raman scattering results reveal the presence of vacancy-hydrogenated complex in the post-annealed samples. Raman mapping around blisters suggests that there is more internal stress around the periphery of blisters than at its centre. Internal pressure and stress inside the blisters are estimated using Föppl-von Karman's (FvK) theory of thin plates. The internal pressure decreases with the diameter of the blisters. FvK theory of thin plates has enabled the determination of a threshold stress of 0.06 GPa, describing the change from a tensile to a compressive stress state in the buckles, which leads to the exfoliation of blisters. [ABSTRACT FROM AUTHOR]

Integrating diamonds with GaN presents a promising solution for enhancing heat dissipation. However, a critical challenge lies in developing an engineering substrate that facilitates the growth of high-quality GaN epitaxial layers, enabling the production of GaN-based devices with superior thermal management on a large scale. In this study, we have successfully developed an engineering substrate conducive to high-quality GaN growth. This accomplishment was achieved through the direct transfer of a 3 C-SiC thin film, originally grown on Si, to a diamond substrate at room temperature using the surface-activated bonding technique. After the transfer process, we observed the presence of a SiC amorphous layer at the interface, measuring approximately 18.5 nm in thickness. Notably, this thickness reduced to 14.5 nm after annealing at 1100 °C, indicating a transformation from amorphous to polycrystalline SiC due to recrystallization. Furthermore, it is crucial to highlight that no exfoliation of the 3 C-SiC/diamond bonding interfaces was observed even after subjecting them to annealing at 1100 °C. This observation is pivotal for ensuring the high-quality growth of GaN crystals on diamonds. The thermal boundary conductance of the 3 C-SiC/diamond interface reached nearly 93 MW/m2·K, demonstrating significant efficiency for device cooling. These compelling results highlight the potential of the 3 C-SiC/diamond engineering substrate to enable high-performance GaN-based devices, providing significantly enhanced thermal management capabilities. This breakthrough represents a major stride forward in the field.

Solution growth is a promising method for rapidly and stably preparing high-quality silicon carbide (SiC) single crystals. However, the coexistence of polycrystalline parasitism and solid inclusions during the growth of SiC in high-temperature solutions above 1800 °C still poses a serious threat to the quality of single crystals. Herein, we introduce an innovative Mn-based cosolvent for controlling the stable and fast growth of cubic-type silicon carbide (3C–SiC) single crystals at low temperatures. Firstly, our thermodynamic analysis reveals that SiC is the only stable solid compound in the low-temperature solution (1500–1600 °C) of the Si–Mn–C system, which is an important condition for the stable growth of crystals. Compared to typical solvents like Si–Cr, Si–Ti, and Si–Fe, the Si–Mn solvent exhibits the highest solubility and supersaturation for carbon. Secondly, our solubility calculations of SiC in the solvent show that the Mn-rich solvent can significantly increase the solubility of SiC. Thirdly, we successfully grew 3C–SiC single crystals from Si–Mn solution at 1500 °C without other SiC polymorphs produced. Rapid growth of SiC crystals in Mn-rich solution was achieved by modulating the content of Mn. Our work highlights the superiority of Si–Mn cosolvents in facilitating rapid growth of 3C–SiC single crystals at low temperatures. It introduces a novel approach by applying phase diagram calculation techniques to design suitable solvent systems for the solution growth of SiC single crystals. [ABSTRACT FROM AUTHOR]

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We demonstrate the growth of 3C-SiC with reduced planar defects on a micro-scale compliant substrate. Heteroepitaxial growth of 3C-SiC on trenches with a width and separation of 2 µm, etched into a Si(001) substrate, is found to suppress defect propagation through the epilayer. Stacking faults and other planar defects are channeled away from the center of the patterned structures, which are rounded through the use of H2 annealing at 1100 °C. Void formation between the columns of 3C-SiC growth acts as a termination point for defects, and coalescence of these columns into a continuous epilayer is promoted through the addition of HCl in the growth phase. The process of fabricating these compliant substrates utilizes standard processing techniques found within the semiconductor industry and is independent of the substrate orientation and offcut. [ABSTRACT FROM AUTHOR]

Background3C-SiC (β-SiC) exhibits outstanding electrochemical properties and radiation resistance, surpassing hexagonal-phase silicon carbide in irradiation resistance. As a promising candidate for the next generation of structural materials in nuclear applications and high-performance precision electronic devices for challenging reactor environments, the material has been garnering significant attention in recent decades. Within this realm, the exploration of one-dimensional silicon carbide nanomaterials has become a focal point in silicon carbide materials research. However, their practical applications have been hindered by challenges such as the absence of effective nanomaterial processing methods and processing complexities. Notably, ultrasonic processing technology has demonstrated effectiveness in addressing these challenges.PurposeThis study aims to synthesize and study 3C-SiC nanowires (NWs), investigating their ultrasonic fracture behavior for comprehensive understanding of the ultrasonic fracture characteristics of 3C-SiC NWs, laying the groundwork for basic research in the processing of one-dimensional SiC nanomaterials.MethodsFirstly, silicon carbide nanowires were prepared by chemical vapor deposition. Then the silicon carbide nanowires were characterized by microstructure observed by scanning electron microscope (SEM), transmission electron microscope (TEM), X-Ray diffraction (XRD) and Raman spectrum. Subsequently, the 3C-SiC nanowires were subjected to ultrasonic treatment, and the average length-to-diameter ratios of the ultrasonically treated nanowires were statistically analyzed to elucidate the effect of ultrasonic treatment on the nanowires. Finally, the strength of the silicon carbide nanowires was estimated by combining the bubble jet model and statistical data.ResultsThe findings reveal that the synthesized 3C-SiC NWs are predominantly of the 3C-SiC phase, exhibiting a notable presence of stacking faults. Ultrasonic treatment significantly influences the SiC NWs, leading to a noticeable reduction in the average Length-Diameter ratio, stabilizing at 18 post-treatment.ConclusionsThe observed results align with the effects of bubble jetting and are corroborated by the ultrasonic fragmentation behavior of 3C-SiC NWs. These findings offer valuable insights for the manipulation of nanomaterial size and morphology. This study provides a new perspective for the ultrasonic cutting of silicon carbide nanowires and the strength research of nanowires, and is of great significance for the future application of silicon carbide nanowires in the field of nuclear energy.

3C silicon carbide (3C-SiC) has great potential and value for innovated high-precision devices. However, the high hardness make it a daunting task to understand its deformation behavior and anisotropy effect, which impedes its processing and application. In this study, we performed molecular dynamic simulations of nanoindentation to study the deformation behavior and anisotropy effect of 3C-SiC. It is found that the elastic deformation and incipient plastic deformation are orientation-dependent, exhibiting fourfold symmetry, central symmetry and threefold symmetry while indenting on 3C-SiC (010), (110) and (111) surfaces. The dislocations nucleate and propagate due to the high shear stress induced by indentation, which in turn leads to the dissipation of shear stress in the sample. In the plastic stage, the dislocations evolve from embryonic dislocations to ribbon dislocations, and finally to prismatic dislocations. The prismatic dislocation loops are surrounded by stacking faults in {111} planes, most of which are enclosed by four stair-rod dislocations in orientations. Moreover, we find that Thompson tetrahedron is suitable for understanding the anisotropy effect of ceramics with cubic diamond structure, and it is applied to investigate the formation and evolution of dislocations systematically in 3C-SiC. This research is meaningful for understanding the deformation behavior and anisotropy effect of 3C-SiC. The results may provide theoretical support for the processing and application of 3C-SiC.

Single crystal 3C-SiC as a typical hard and brittle material. Due to its extremely high hardness and brittleness, diamond tools can have drastic wear problems in a short period of time when performing nano-machining processes. Single-crystal 3C-SiC has good anisotropy. In order to gain insight into the effect of crystal orientation on the tool wear behavior during nano-cutting, this paper investigated the tool wear for six cutting crystals downward using molecular dynamics simulation. The tool wear process was analyzed in terms of tool wear, cutting stress, cutting temperature, cutting force and subsurface damage. The results showed that the tool is subjected to large hydrostatic stress concentrations, radial forces and tool temperature concentrations during machining. Under these effects, abrasive wear, graphitic wear and amorphous phase change were produced. In addition, the clearance face of the tool is more severely worn than the rake face. By reasonably selecting the cutting crystal orientation, well control and improvement of tool wear and machined surface quality can be achieved. [ABSTRACT FROM AUTHOR]

In this investigation, we develop CdS-free non-toxic thin-film solar cell structure with antimony sulfide (Sb2S3) as an absorber material. Sb2S3 has found to be a promising candidate for production of renewable energy. Solar cells based on Sb2S3 have been attracted worldwide attraction due to their outstanding efficiency and low cost. To serve as an optimistic buffer layer, 3C-SiC (cubic silicon carbide) is used thanks to its suitable bandgap to replace toxic cadmium sulfide (CdS). SCAPS-1D (one-dimensional solar cell capacitance simulator) software has been employed to numerically investigate the performance of Sb2S3-based n-ZnO/n-3C-SiC/p-Sb2S3 heterostructure solar cells. The influence of absorber/buffer layer thickness, acceptor/donor densities, and defect density on device working have been investigated. Consequently, the role of defects in p-Sb2S3 along with the significance of n-3C-SiC/p-Sb2S3 interface defects has been studied to provide recommendations for achieving high efficiency. The proposed structure provides the enhanced efficiency of 17% under 1.5 G illumination spectrum. The parameters regarding solar cell performance such as Voc, Jsc, FF, QE and η have been studied graphically. This novel structure may have considerable influence on progress of improved photovoltaic devices in future. [ABSTRACT FROM AUTHOR]

Changes in the atomic and electronic structure of silicon carbide 3C-SiC (β-SiC), resulting from lead adsorption, were studied within the density functional theory. The aim of the study was to analyze the main mechanisms occurring during the corrosion of this material. Therefore, the investigations focused on process-relevant parameters such as bond lengths, bond energies, Bader charges, and charge density differences. To compare the magnitude of the interactions, the calculations were conducted for three representative surfaces: (100, 110, and 111) with varying degrees of lead coverage. The results indicate that chemisorption occurs, with the strongest binding on the hexagonal surface (111) in interaction with three dangling bonds. The adsorption energy rises with increasing coverage, especially as the surface approaches saturation. As a result of these interactions, atomic bonds on the surface weaken, which affects the dissolution corrosion. [ABSTRACT FROM AUTHOR]

Metal-oxide-semiconductor (MOS) capacitors with Al2O3 as a gate insulator are fabricated on cubic silicon carbide (3C-SiC). Al2O3 is deposited both by thermal and plasma-enhanced Atomic Layer Deposition (ALD) on a thermally grown 5 nm SiO2 interlayer to improve the ALD nucleation and guarantee a better band offset with the SiC. The deposited Al2O3/SiO2 stacks show lower negative shifts of the flat band voltage VFB (in the range of about −3 V) compared with the conventional single SiO2 layer (in the range of −9 V). This lower negative shift is due to the combined effect of the Al2O3 higher permittivity (ε = 8) and to the reduced amount of carbon defects generated during the short thermal oxidation process for the thin SiO2. Moreover, the comparison between thermal and plasma-enhanced ALD suggests that this latter approach produces Al2O3 layers possessing better insulating behavior in terms of distribution of the leakage current breakdown. In fact, despite both possessing a breakdown voltage of 26 V, the T-ALD Al2O3 sample is characterised by a higher current density starting from 15 V. This can be attributable to the slightly inferior quality (in terms of density and defects) of Al2O3 obtained by the thermal approach and, which also explains its non-uniform dC/dV distribution arising by SCM maps. [ABSTRACT FROM AUTHOR]

In this paper, pure Ni foil was used as an intermediate layer to achieve brazing connection of 6H-SiC at 1 100 ~ 1 245 °C. The microstructure of the brazed joint and the interface between the brazed joint and the 6H-SiC substrate were studied to investigate the effect of brazing process on the crystal structure of SiC ceramics and provide theoretical and experimental data supports for brazing process design. The results show that a small amount of Ni atoms diffuse into the 6H-SiC ceramics during the brazing process and exist in solid solution form, which reduces the dislocation energy of 6H-SiC. The residual stress at the 6H-SiC/brazed joint interface increases with the increase of brazing temperature, and when the brazing temperature reaches 1 245°C, the (0001) plane of 6H-SiC at the interface slips along the 1/3 < 1100 > direction, and the 6H-SiC is sheared to form 3C-SiC. Therefore, SiC ceramics can undergo phase transformation under the influence of stress and brazing material composition during the brazing process, and the effect of brazing process on their crystal structure and properties should be considered for SiC ceramics used in special environments. [ABSTRACT FROM AUTHOR]

3C-SiC/4H-SiC heterostructures have great potential for high-electron-mobility transistors. The growth of high-quality 3C-SiC epilayers on 4H-SiC substrates can be realized by controlling step growth with proper surface pretreatment. We investigated the optical and electrical properties of extended defects in 3C-SiC by cathodoluminescence (CL) spectroscopy. CL images revealed the distribution of extended defects in 3C-SiC. The impact of surface pretreatment on the growth of high-quality 3C-SiC is discussed. [ABSTRACT FROM AUTHOR]

Using industrial coal and ethyl orthosilicate as raw materials and NiCl2 as catalyst, the microwave-induced catalyst was used to synthesize SiC fibers. The effects of catalyst concentration and temperature on SiC fibers were discussed, and the microwave-absorbing properties of SiC fibers were studied. The products were characterized by X-ray diffraction, field emission scanning electron microscope and vector network analyzer. The results show that various morphologies of SiC can be formed by NiCl2 catalyst with different concentration. When the catalyst concentration is 5%, nano-SiC fibers can be formed. SiC can be prepared by microwave heating at 900 ℃ for 30 min under the action of 5% NiCl2 catalyst. The magnetic linear Si-Ni compounds formed during the preparation process can promote the rapid formation of SiC fibers. When the thickness of SiC fiber is 4mm and the frequency is 4.06 GHz, the RL of SiC fiber reaches-36.74 dB, showing excellent electromagnetic wave absorption performance. The results provide theoretical and experimental basis for microwave induced preparation of high performance wave absorbing SiC fibers. [ABSTRACT FROM AUTHOR]

A systematic approach to determine the most crucial growth parameters and their effect on the surface morphology and defect density of sublimation grown (001) cubic silicon carbide (3C‐SiC) is conducted. Close space physical vapor transport (CS‐PVT) growth on 3C‐SiC and 4° off oriented homoepitaxial chemical vapor deposition (CVD) grown seeding layers is performed. For each growth run, one growth parameter, e.g., temperature, pressure, or N2 flux is varied, while the other parameters are kept constant. Raman spectroscopy, potassium hydroxide (KOH) etching, as well as optical microscopy and atomic force microscopy (AFM) are used for the sample characterization. Step‐flow‐controlled growth is observed on all grown samples, while the stacking fault density is generally reduced with respect to the seeding layers. Increased temperature as well as increased pressure leads to roughening of the growth surface attributed to step bunching, while their effect on the stacking fault density seems to be only minor in the analyzed parameter range. Areas of strongly enhanced step bunching are present on all samples, and this effect is more pronounced at higher temperature and pressure. Increased nitrogen doping leads to a decreased stacking fault density but also increases the length of remaining stacking faults. The surface morphology is influenced by N2 on a macroscopic level rather than on microscopic scale. [ABSTRACT FROM AUTHOR]

In this paper, we used micro-Raman spectroscopy in cross-section to investigate the effect of different doping on the distribution of stress in the silicon substrate and the grown 3C-SiC film. The 3C-SiC films with a thickness up to 10 μm were grown on Si (100) substrates in a horizontal hot-wall chemical vapor deposition (CVD) reactor. To quantify the influence of doping on the stress distribution, samples were non-intentionally doped (NID, dopant incorporation below 1016 cm−3), strongly n-type doped ([N] > 1019 cm−3), or strongly p-type doped ([Al] > 1019 cm−3). Sample NID was also grown on Si (111). In silicon (100), we observed that the stress at the interface is always compressive. In 3C-SiC, instead, we observed that the stress at the interface is always tensile and remains so in the first 4 µm. In the remaining 6 µm, the type of stress varies according to the doping. In particular, for 10 μm thick samples, the presence of an n-doped layer at the interface maximizes the stress in the silicon (~700 MPa) and in the 3C-SiC film (~250 MPa). In the presence of films grown on Si(111), 3C-SiC shows a compressive stress at the interface and then immediately becomes tensile following an oscillating trend with an average value of 412 MPa. [ABSTRACT FROM AUTHOR]

The paper reviews the development of the 3C-SiC MOSFETs in a unique development project combining the material and device expertise of HAST (Hoya Advanced Semiconductor Technologies) and Acreo, respectively. The motivation for the development of the 3C-SiC MOSFETs and the summary of the results from the lateral and vertical devices with varying size from single cell to 3×3 mm2 large devices are reviewed. The vertical devices had hexagonal and square unit cell designs with 2 μm and 4 μm channel length. The p-body was aluminum implanted and the source was nitrogen or phosphorus implanted. Low temperature Ti/W contacts were evaluated.

Various crystalline silicon carbide (SiC) polytypes are emerging as promising photonic materials due to their wide bandgap energies and nonlinear optical properties. However, their wafer forms cannot readily provide a refractive index contrast for optical confinement in the SiC layer, which makes it difficult to realize a SiC-based integrated photonic platform. In this paper, we demonstrate a 3C-SiC-on-insulator (3C-SiCoI)-based integrated photonic platform by transferring the epitaxial 3C-SiC layer from a silicon die to a borosilicate glass substrate using anodic bonding. By fine-tuning the fabrication process, we demonstrated nearly 100% area transferring die-to-wafer bonding. We fabricated waveguide-coupled microring resonators using sulfur hexafluoride (SF6)-based dry etching and demonstrated a moderate loaded quality (Q) factor of 1.4 × 105. We experimentally excluded the existence of the photorefractive effect in this platform at sub-milliwatt on-chip input optical power levels. This 3C-SiCoI platform is promising for applications, including large-scale integration of linear, nonlinear and quantum photonics. [ABSTRACT FROM AUTHOR]

Wide bandgap semiconductors doped with transition metals are attracting significant attention in the fabrication of dilute magnetic semiconductor devices (DMSs). The working principle of DMSs is based on the manipulation of the electron spin, which is useful for magnetic memory devices and spintronic applications. Using the density functional theory (DFT) calculation with the GGA+U approximation, we investigated the effect of native defects on the magnetic and electronic structure of Mn+2-doped 3C-SiC structure. Three structures were selected with variations in the distance between two impurities of (Mn+2)-doped 3C-SiC, which are 4.364 Å, 5.345Å, and 6.171 Å, respectively. We found ferromagnetic coupling for single and double Mn+2 dopant atoms in the 3C-SiC structure with magnetic moments of 3   μ B and 6 μ B respectively. This is due to the double exchange because of p-d orbital hybridization. The p-orbitals of C atoms play important roles in the stability of the ferromagnetic configuration. The impact of Si-vacancy (nearby, far) and C-vacancy (near) of (Mn+2)-doped 3C-SiC plays an important role in the stabilization of AFM due to super-exchange coupling, while the C-vacancy (far) model is stable in FM. All electronic structures of Mn+2-doped 3C-SiC reveal a half-metallic behavior, except for the Si-vacancy and C-vacancy of (nearby), which shows a semiconductor with bandgap of 0.317 and 0.828 eV, respectively. The Curie temperature of (Mn+2)-doped 3C-SiC are all above room temperature. The study shows that native vacancies play a role in tuning the structure from (FM) to (AFM), and this finding is consistent with experiments reported in the literature. [ABSTRACT FROM AUTHOR]

The molecular dynamics method was used to analyze the influence of simulated temperature on the damage expansion process of the 3C-SiC sample under nano-indentation loading in order to study the influence of temperature on the internal damage and expansion mechanism of the 3C-SiC single crystal sample further during the nano-indentation loading process. A simulation test platform for diamond indenter indentation was established. The process of stress and strain distribution, dislocation evolution, dislocation expansion and potential energy change were analyzed, combined with the radial distribution function and load displacement curve. The influence of temperature on the 3C-SiC material was discussed. The variation trend of the potential energy-step curve is basically the same at the temperatures of 0 K, 300 K, 600 K and 900 K. The difference in strain distribution was characterized by the influence of temperature on stress intensity, expansion direction and type. The microcosmic manifestation is the significant difference in the dislocation slip at low temperature. In the process of dislocation evolution and expansion, dislocation climbs at room temperature and increases at high temperature, which is closely related to energy release. This study has certain guiding significance for investigating the internal damage difference and temperature effect of the 3C-SiC sample. [ABSTRACT FROM AUTHOR]

Recent analyses of neutron-irradiated cubic silicon carbide (3C-SiC) samples using Fourier-transform infrared spectroscopy (FTIR spectroscopy) reported on observed changes of the reflectance as well as extracted dielectric parameters of the samples. The changes were thought to be associated with sample surface roughness. Since neutron irradiation is not expected to damage the surface of irradiated samples, these observations were reassessed. It is suggested that changes could more likely be ascribed to the grain sizes of the polycrystalline 3C-SiC samples that were irradiated. [ABSTRACT FROM AUTHOR]

We studied the optical and positron annihilation properties of N C V Si in 3 C -SiC using first-principles calculations. We found that the charge-state transition and the spin-conserving optical transition levels are very close to each other. In order to distinguish between the NV center and intrinsic defect, we calculate in detail the defect formation energies, temperature-dependent positron lifetimes, and electron-positron momentum distribution of these defects in 3 C -SiC. We suggest that using positrons technique alone is insufficiently sensitive in identifying the charge-states of N C V Si , necessitating the use of additional characterization methods to address this issue. • The optical transition levels for the charge-state transition and spin-conservation of the NV center in 3 C -SiC are similar. • The first calculation of the temperature-dependent positron lifetime of NV center in 3 C -SiC. • The momentum distribution of NV center in different charged states is very similar. [ABSTRACT FROM AUTHOR]

The hetero-epitaxial growth of 3C–SiC layers on on-axis 4H–SiC substrates has been demonstrated in a hot-wall CVD reactor using trichlorosilane and ethylene as precursors. The additional chlorine is supplied by hydrogen chloride for variation of Cl/Si ratio. The influence of temperature, C/Si ratio and Cl/Si ratio process parameters on the morphology is studied. Double-position-boundaries free 3C–SiC epitaxial layers have been successfully grown at the optimized condition, which is at a temperature of 1340 °C, with C/Si = 0.6 and Cl/Si = 6 using a carbon-rich pretreatment. Low temperature near bandgap photoluminescence shows a good optical property of the obtained 3C–SiC epitaxial layers. Compared to the standard chemistry, a higher growth rate of 12 μm/h could be achieved by utilizing the chlorinated precursors. This study provides a feasible way to grow double-position-boundaries free 3C–SiC epitaxial layers using TCS as silicon precursor. • The 3C–SiC epilayers were CVD grown on 4H–SiC using TCS as silicon precursor. • Smooth 3C–SiC layers without any DPB defects could be grown with optimized process. • The growth rate could be achieved to 12 μm/h for 3C–SiC layers with smooth surface. [ABSTRACT FROM AUTHOR]

This study examined the temperature-related piezoresistance issues of p-type doped 3C-silicon carbide (3C-SiC) materials. Previously, we proposed piezoresistance temperature models that describe phenomena based on the ionization energies of materials oriented for high-temperature operations. This study aimed to determine the ionization energy as a function of the aluminum doping concentration of 3C-SiC. However, at the low-temperature region a drastic decrease in the piezoresistive coefficient was observed, and it was predicted to occur when materials possessing large impurity ionization energy are used under negative thermal strained conditions. This phenomenon is in contrast to the conventional piezoresistance factor $P(N,T)$ that is based on narrow band-gap materials such as silicon or germanium; thus, it provides new insights into low-temperature piezoresistance phenomena.

High power laser transmission technology is based on energy transfer through a monochromatic laser onto a photovoltaic receiver avoiding the limitations of conventional wiring. Current technology, headed by GaAs‐based devices, faces two limitations: the intrinsic entropic losses and the degradation at high input power densities due to ohmic losses. Two novel laser power converters focused on overcoming these limitations are proposed. 3C‐SiC is used as base material because of its high bandgap (2.36 eV) and its excellent crystallographic properties in order to reduce the entropic losses. Also, the current decreases due to the inherent flux reduction of high energy photons. To minimize ohmic losses, a recently proposed vertical architecture is explored, which can significantly reduce series resistance around two orders of magnitude (≈10−5 Ω cm2). Furthermore, 3C‐SiC is also implemented in a conventional horizontal architecture to show the advantage of increasing the energy gap to reduce the ohmic losses. The two laser power converters obtain efficiencies above the state‐of‐the‐art (87.4% at 3000 W cm−2 for the vertical architecture and 81.1% at 100 W cm−2 for the horizontal architecture) Taking this into account, the new devices open a new route for ultrahigh efficiency remote powered systems. [ABSTRACT FROM AUTHOR]

We fabricated n-channel MOSFETs with various gate dielectrics on (111) oriented 3C-SiC/Si. Fabricated MOSFETs operated as inversion mode devices successfully. The MOSFET with sputter-deposited SiO2/plasma oxidized interlayer showed a high peak field-effect mobility of 131 cm2 Vâˆ'1 sâˆ'1. The gate stack can be formed at a low temperature of 400 °C, which means the process is absolved from high-temperature thermal oxidation for a gate stack. The detailed analysis of charges and traps in the gate stacks clarified that Coulomb scattering is well-suppressed in the inversion channel. These results will be the first step for a high-performance 3C-SiC application, including on-chip hetero-integrated electronic devices. [ABSTRACT FROM AUTHOR]

The annealing-promoted He release process in irradiated SiC remains unclear. Herein the atomistic release behavior of a He atom from 3 C -SiC(1 0 0) subsurface is investigated by density functional theory calculations. The results show that the interstitial He atom in the 3 C -SiC(1 0 0) subsurface tends to diffuse to the surface by overcoming a diffusion barrier of 0.72 eV, rather than to infiltrate into the slab interior, supporting a bulk-diffusion-limited mechanism for He release from SiC. The He atom can spontaneously diffuse on the 3 C -SiC(1 0 0) surface, suggesting a retarding effect on He release from irradiated SiC. The results provide deeper insight into the release mechanism of He defects in irradiated SiC and are useful for improving defect recovery strategies. [ABSTRACT FROM AUTHOR]

In this paper, we will provide information on the growth mechanism of 3C-SiC using alternating supply deposition (ASD). SiH 4 and C 3 H 8 were introduced successively in a low-pressure chemical vapor deposition (LPCVD) system at 1000 °C, forming a stoichiometric polycrystalline 3C-SiC thin film on Si substrates. We demonstrate the influence of different gas flow rates on thin film properties. In detail, altering the flow rates of the precursors and the carrier gas resulted in changes of the growth rate, the surface roughness, the crystal growth mechanisms as well as the crystal quality. Hydrogen inhibition and passivation are proposed to be the main effects influencing the growth behavior of ASD thin films. Applying ASD to grow 3C-SiC thin films with precursors from low to high flow rates resulted in a transition of different growth mechanisms influencing the surface roughness and grain size. Furthermore, we could prove that ASD is a cyclic step-by-step carbon-assisted redistribution of a prior deposited silicon film. This is shown by contact angle measurements of three differently terminated surfaces during the specific phases of one ASD cycle. High resolution transmission electron microscopy (HRTEM) analysis showed a continuous and homogenous thin film and confirmed the absence of silicon- or carbon-rich layers. ASD enables 3C-SiC thin films with customized properties for tailored micro electromechanical system (MEMS) applications. [Display omitted] • Tailored 3C-SiC thin film properties for MEMS applications using alternating supply deposition (ASD). • Discussion of control parameters affecting 3C-SiC properties during deposition. • Changes of the gas flow shows high impact on the roughness and crystallinity. • Characterization of the carbonization layer at the 3C-SiC/Si interface. • Insights into alternating supply deposition (ASD) growth mechanism. [ABSTRACT FROM AUTHOR]

We fabricate AlGaN/GaN high electron mobility transistors (HEMTs) on diamond substrates by transferring 8 μ m heterostructures grown on 3C-SiC/Si templates and subsequently applying the conventional device process steps. No exfoliation of 3C-SiC/diamond bonding interfaces is observed during 800 °C annealing, the essential step for forming ohmic contacts on nitrides. The thermal resistance of HEMTs on diamond is 35% of that of HEMTs on Si, which is assumed to be the origin of smaller negative drain conductance in on-diamond HEMTs. The results imply that the bonding-first process is applicable for fabricating low-thermal-resistance HEMTs with thick nitride layers. [ABSTRACT FROM AUTHOR]

ملخص البحث: فی هذا البحث، لقد تم استخدام مادة 3C-SiC و المشوبة مع عنصرین وهما Al و Cr للحصول على خصائص شبه الموصل من النوع p و n على التوالی، کمکون أساسی فی بنیة الخلیة الشمسیة المستخدمة حالیا فی هذه الدراسة. حیث ترکزت الدراسة الحالیة على تأثیر الظروف البیئیة الرئیسیة وهما (درجة الحرارة وشدة الاضاءة) على اداء الخلیة الشمسیة الحالیة من نوع PIN . حیث تم اعتماد مستویات مختلفة من شدة الاضاءة من (250 الى 1200) وات.م2-وکذلک درجات حرارة متغیرة فی المدى من (300 الى400) کلفن فی المحاکاة. لقد أظهرت النتائج إلى أن شدة الضوء لها تأثیر فعال على تیار الدائرة، حیث تزداد قیمة تیار الدائرة القصیرة JSC خطیًا مع زیادة مستوى شدة الضوء الساقط. وکذلک، فقد أظهرت النتائج أن درجة الحرارة لها تأثیر کبیر على معلمات جهد الخلیة. حیث لوحظ ان جهد الدائرة المفتوحة VOC ینخفض بشکل کبیر بسبب انخفاض تیار التشبع والذی بدوره یتناقص بسرعة مع زیادة درجة الحرارة.

Wide bandgap semiconductors doped with transition metals are attracting significant attention in the fabrication of dilute magnetic semiconductor devices (DMSs). The working principle of DMSs is based on the manipulation of the electron spin, which is useful for magnetic memory devices and spintronic applications. Using the density functional theory (DFT) calculation with the GGA+U approximation, we investigated the effect of native defects on the magnetic and electronic structure of Mn+2-doped 3C-SiC structure. Three structures were selected with variations in the distance between two impurities of (Mn+2)-doped 3C-SiC, which are 4.364 Å, 5.345Å, and 6.171 Å, respectively. We found ferromagnetic coupling for single and double Mn+2 dopant atoms in the 3C-SiC structure with magnetic moments of 3 μB and 6 μB respectively. This is due to the double exchange because of p-d orbital hybridization. The p-orbitals of C atoms play important roles in the stability of the ferromagnetic configuration. The impact of Si-vacancy (nearby, far) and C-vacancy (near) of (Mn+2)-doped 3C-SiC plays an important role in the stabilization of AFM due to super-exchange coupling, while the C-vacancy (far) model is stable in FM. All electronic structures of Mn+2-doped 3C-SiC reveal a half-metallic behavior, except for the Si-vacancy and C-vacancy of (nearby), which shows a semiconductor with bandgap of 0.317 and 0.828 eV, respectively. The Curie temperature of (Mn+2)-doped 3C-SiC are all above room temperature. The study shows that native vacancies play a role in tuning the structure from (FM) to (AFM), and this finding is consistent with experiments reported in the literature.

Various crystalline silicon carbide (SiC) polytypes are emerging as promising photonic materials due to their wide bandgap energies and nonlinear optical properties. However, their wafer forms cannot readily provide a refractive index contrast for optical confinement in the SiC layer, which makes it difficult to realize a SiC-based integrated photonic platform. In this paper, we demonstrate a 3C-SiC-on-insulator (3C-SiCoI)-based integrated photonic platform by transferring the epitaxial 3C-SiC layer from a silicon die to a borosilicate glass substrate using anodic bonding. By fine-tuning the fabrication process, we demonstrated nearly 100% area transferring die-to-wafer bonding. We fabricated waveguide-coupled microring resonators using sulfur hexafluoride (SF6)-based dry etching and demonstrated a moderate loaded quality (Q) factor of 1.4 × 105. We experimentally excluded the existence of the photorefractive effect in this platform at sub-milliwatt on-chip input optical power levels. This 3C-SiCoI platform is promising for applications, including large-scale integration of linear, nonlinear and quantum photonics.

The molecular dynamics method was used to analyze the influence of simulated temperature on the damage expansion process of the 3C-SiC sample under nano-indentation loading in order to study the influence of temperature on the internal damage and expansion mechanism of the 3C-SiC single crystal sample further during the nano-indentation loading process. A simulation test platform for diamond indenter indentation was established. The process of stress and strain distribution, dislocation evolution, dislocation expansion and potential energy change were analyzed, combined with the radial distribution function and load displacement curve. The influence of temperature on the 3C-SiC material was discussed. The variation trend of the potential energy-step curve is basically the same at the temperatures of 0 K, 300 K, 600 K and 900 K. The difference in strain distribution was characterized by the influence of temperature on stress intensity, expansion direction and type. The microcosmic manifestation is the significant difference in the dislocation slip at low temperature. In the process of dislocation evolution and expansion, dislocation climbs at room temperature and increases at high temperature, which is closely related to energy release. This study has certain guiding significance for investigating the internal damage difference and temperature effect of the 3C-SiC sample.

In the present study, molecular dynamics (MD) simulations are applied to investigate the polishing process of cubic silicon carbide (3C-SiC) with a rotating abrasive. The influence of abrasive rotational speed and rotation axis orientation on the friction characteristics and deformation behaviors of 3C-SiC is studied. The results show that as the rotational speed increases, the normal force first increases until it reaches its maximum at 25 rad/ns and then decreases. The evolution of transverse force with the rotational speed is more complicated and the smallest transverse force and friction coefficient are obtained at the rotational speed of 50 rad/ns. Besides, the transverse force increases while the normal force decreases with the rotation angle when the angular velocity vector of the rotational abrasive is parallel to the substrate surface. The case when the rotational speed is 25 rad/ns and the rotation angle is 0 is a significant critical situation. At the critical situation, we observe the lowest material removal rate, the deepest subsurface damage layer, the biggest high stress region and the smallest high temperature region for all rotational speeds and rotation axis orientations. Moreover, in the simulations, phase transformation (mainly amorphization) induced by high pressure is more pronounced than that by thermal effect. The results gained can shed light on the atomic-scale material removal and deformation mechanisms of 3C-SiC during polishing process. [ABSTRACT FROM AUTHOR]

• Novel buffer layer 3C-SiC used in CIGS thin-film solar cell. • Highest efficiency of 25.51% is achieved at ΔE c = 0.91 eV or E g (CIGS) = 1.45 eV for 50 nm thin 3C-SiC buffer layer. • Existence of interface recombination centers yielded activation energy of 1.417 eV. • Proposed structure shows good thermal stability, as J sc increases by 0.04%/K and V oc decreases on an average by 1.77 mV/K. Cubic Silicon Carbide (3C-SiC) can be a potential photovoltaic material for thin-film solar cells because of its wide bandgap and non-toxic nature. In this work, we present 3C-SiC as an alternative to the conventional CdS buffer layer and investigate the performance of the proposed 3C-SiC/CIGS cell structure using solar simulator SCAPS-1D. The simulation starts with the optimization of 3C-SiC buffer layer thickness followed by the study of conduction band offsets (CBO) impact on the photovoltaic performance parameters. The highest obtained efficiency is 25.51% (V oc = 0.94 V, J sc = 31.46 mA/cm2) at CBO, ΔE c = 0.91 eV with the optimized buffer thickness. The linear extrapolation study of V oc as a function of temperature yields the activation energy which tells the existence of interface recombination centres. Next, the inclusion of the acceptor defect state at the 3C-SiC/CIGS interface determines the maximum acceptable defect density of the proposed cell structure. Afterward, the thermal stability through temperature study is performed and compared to the traditional CdS/CIGS structure. The results provided here give few paramount indications that lead to a highly efficient CIGS solar cell with a 3C-SiC buffer layer. [ABSTRACT FROM AUTHOR]

This communication presents a comparative study on the charge transport (in transient and steady state) in bulk n-type doped SiC-polytypes: 3C-SiC, 4H-SiC and 6H-SiC. The time evolution of the basic macrovariables: the "electron drift velocity" and the "non-equilibrium temperature" are obtained theoretically by using a Non-Equilibrium Quantum Kinetic Theory, derived from the method of Nonequilibrium Statistical Operator (NSO). The dependence on the intensity and orientation of the applied electric field of this macrovariables and mobility are derived and analyzed. From the results obtained in this paper, the most attractive of these semiconductors for applications requiring greater electronic mobility is the polytype 4H-SiC with the electric field applied perpendicular to the c-axis. [ABSTRACT FROM AUTHOR]

During the process of nano grinding 3C–SiC, amorphous phase transformation and dislocation damage layers are generated. The size and cutting-edge height of tetrahedral abrasive grains are studied, and the 3C–SiC grinding mechanism under the coupling effect of tetrahedral multi abrasive grains is studied using molecular dynamics method. It is found that when the maximum cutting-edge height of appropriate sized abrasive grains meets a certain size height, only phase transformation is generated on the surface of the workpiece without dislocations. This result helps guide the grinding process of 3C–SiC and provides a theoretical basis for the design of tetrahedral abrasive grinding discs. [ABSTRACT FROM AUTHOR]

A qualitative and quantitative study was performed on the carbonization temperature (TC) and carbonization time (tC) with respect to the microstructure and growth rate (Rg) of a 3C-SiC epitaxial layer on Si (111) substrates by carbonization via laser chemical vapor deposition (LCVD). The results showed that the density and size of the voids depended strongly on TC. The voids were sealed, and thin films were formed continuously and uniformly after a carbonization time of 6 min at TC = 1200 °C. Rg was also dependent on TC, and increased from 0.43 to 1.35μm·h−1 with increases in TC from 1000 to 1200 °C. These deposition rates are 10 to 100 times greater than those of observed for conventional CVD methods.

Understanding which morphology is most stable for one-dimensional (1D) SiC nanostructures at high temperature with long-term operation is highly desired since it is vitally important for the development of reliable SiC nanostructures-based devices for use in harsh working conditions. In this communication, we report the controlled growth of 1D 3 C –SiC nanostructures with tailored morphologies based on catalyst-assisted polymeric pyrolysis by controlling the applied temperatures. The results demonstrated that cylindrically shaped 1D SiC nanostructures are unstable and can be gradually transformed into triangular prisms via surface diffusion at high temperatures. We demonstrate that this morphology transformation was realized mainly by rearranging energized atoms onto low-index SiC nanostructure surfaces, which is due to the requirement of reducing the overall surface energy. The obtained triangular prisms had smooth surfaces, thereby suggesting a stable morphology (equilibrium crystal shapes). Our results demonstrate that stability can be a contributing factor for reliable application of 1D SiC nanostructures under high temperature. We report the controlled growth of 1D 3 C –SiC nanostructures with tailored morphologies by controlling the pyrolysis temperatures, thereby demonstrating that a triangular prism structure with a smooth surface is the most stable equilibrium crystal shape. [Display omitted] [ABSTRACT FROM AUTHOR]

Semiconductors are well known as excellent materials in the field of exploring novel avenues which combine various fields in electronics, electrochemistry, etc for new functional device concepts. Lithium silicon carbide (LiSiC) is a well-known electrode material for Lithium ion batteries but relatively new for solid oxide fuel cells (SOFCs) and electrolyte-layer free fuel cells (EFFCs). In the present work, we have explored three categories of fuel cells based on mixed LiSiC-SDC (samarium doped ceria) in SOFC and LiSiC as a single component material with type (I) and without coating of a layer of 3CSiC as EFFC type (II). All of three cells are sandwiched between Ni foams coated with NCAL (Ni0.8Co0.15Al0.05Li-oxide). The electrochemical performances of as prepared fuel cells are tested at 550°C, which is substantially lower than in conventional fuel cell materials. The LiSiC based EFFC type (II) demonstrates better performance because of less ohmic resistance as compared to type (I) have more layers. This indicates that the LiSiC-SDC system has potential for fuel cell development in accordance with energy band structure and alignment. [ABSTRACT FROM AUTHOR]