Papers by Keyword: Silicon Carbide (SiC)

Abstract: The silicon carbide was extruded by the batch and sintered under Nitrogen atmosphere using phenolic resin as the main organic plasticizer. The effect of phenolic resin contents on plasticity of the batch, extrusion force and density of the green bodies and the effect of the solidifying law on mechanical properties of products were studied in this paper. The results are as follows: The density and bending strength of sintered bodies reach 3.11 g/cm³ and 320Mpa with 13.6wt% plasticizer content, the extrusion moding can significantly improve the production efficiency and properties of silicon carbide ceramic.

Abstract: In this paper, industrial diamonds using pure Fe powder catalyst with additive Si has been synthesized by HPHT method. Optical microscope, XRD and SEM were utilized for observation and detection. The influences of additive Si on the synthesis have been investigated from several aspects such as the diamond-forming conditions, the composition of synthesized sample and inclusions in diamond, and the morphology character of diamonds etc. The results indicate that the formation of SiC, which should have been in a solid state during the synthesis.

Abstract: This paper presents results of morphological and dimensional characterization of silicon carbide (SiC) abrasives used in production of fickerts for the rotary plane honing and polishing process of porcelain tiles. For morphological characterization scanning electron microscopy (SEM) and optical reflection microscopy images were analyzed by software to determine the circularity factor of the particles. In order to analyze the particle size dispersion sieving and laser diffraction were used. Five samples within the same batch of abrasives and with different sizes were characterized. The results show a uniform dispersion with a small variation of the particles size. Regarding the form of particles, the angularity increases in the samples with smaller size. The employed procedure for the analysis of circularity factor is a method frequently used to characterize SiC particles.

Abstract: To improve the quality of AlN layer deposit on SiC/Si, different Ge amounts (0.25, 0.5, 1, 2ML) were deposited before the carbonization process at the silicon substrate in order to reduce the lattice parameters mismatch between Si and SiC grown layers. The residual stress of the hexagonal AlN layers derives from the phonon frequency shifts of the E1(TO) phonon mode. The crystalline quality of the AlN layer is correlated to and investigated by the full width of the half maximum (FWHM) and the intensity of E1(TO) mode of the 2H-AlN. Best crystalline quality and lower stress value are found in the case where 1ML of Ge amount is predeposited. The E1(TO) mode phonon frequency shifts-down by 3 cm-1/GPa with respect to an unstrained layer.

Abstract: In this work the capability of the proton induced X-ray emission (PIXE) technique to monitor a rapid, non-destructive and accurate quantification of Al on or inside SiC is discussed. Optimization of PIXE acquisition parameters was performed using as reference, a thin Al film (2.5 nm) thermally evaporated onto silicon carbide substrate. In order to improve the sensitivity for Al detection and quantitative determination, a systematic study was undertaken using proton ion beam at different energies (from 0.2 to 3 MeV) with a different tilting angle (0°, 60°, and 80°). The limit of detection (LOD) was found to be lower than 0.02 nm. The optimum PIXE conditions (energy, angle) were applied for determining the Al doping concentration in thin (1 µm) 4H-SiC homoepitaxial layer. The Al concentration as determined by PIXE was found to be 3.9x1020 at/cm3 in good agreement with SIMS measurements, and the LOD was estimated to be 6x1018 at/cm3.

Abstract: This paper focuses on the formation of thin n+p junctions in p-type Silicon Carbide (SiC) epitaxial layers using two kinds of Nitrogen implantations. The standard beam ion implantations and PULSIONTM processes were performed at two distinct energies (700 eV and 7 keV), and the subsequent annealing was held at 1600°C in a resistive furnace specifically adapted to SiC material. No measurable electrical activity was obtained for both implantations performed at 700 eV, due to some outdiffusion of N dopants during the annealing despite a low surface roughness (rms ~ 1.4 nm) and no residual damage detected by RBS/C. A higher sheet resistance was measured in plasma-implanted samples at 7 keV (in comparison with beam-line implanted samples), which is partly related to N outdiffusion. The profiles of N atoms beam-implanted at 7 keV are not affected by the annealing. The corresponding electrical activation is fully completed.

Abstract: Power electronic modules are key elements in the chain of power conversion. The application areas include aerospace, aviation, railway, electrical distribution, automotive, home automation, oil industry ... But the use of power electronics in high temperature environments is a major strategic issue in the coming years especially in transport. However, the active components based on silicon are limited in their applications and not suitable for those require both high voltages and high ambient temperatures. The materials with wide energy gap like SiC, GaN and diamond, have the advantage of being able to exceed these limits [1,2]. These materials seem adequate to extremely harsh temperature environments and allow the reduction of cooling systems, but also the increasing of switching frequency.

Abstract: Gate oxides for SiC lateral MOSFETs have been formed in N2O by rapid thermal processing (RTP) as an alternative to the conventional furnace process. This innovative oxidation method has not only the advantage to significantly reduce the thermal budget compared to a standard oxidation, but also to produce oxide layers with quality comparable to the one grown in a conventional furnace. Moreover, a significant improvement of the oxide quality and MOSFET performance is observed when performing in-situ a H2 anneal prior to oxidation as surface pretreatment. The channel mobility and the breakdown field of the gate oxide are considerably increased.

Abstract: The polytype transitions are caused by disorder generation in the initial structure due to energy dissipation. The disorder is strongly related to the formation and propagation of stacking faults and partial dislocations. Collective and selective interactions between these defects result in a stability loss of the original structure leading to nonequilibrium phase transition occur if the critical point is reached. The stability of the defect subsystem was investigated in the stationary state for three types of stacking faults. The combination of the stability analysis with the defect generation processes during the different technological and devices operation processes allows predicting the critical values for the external forces and fluxes leading to phase transitions.

Abstract: In this paper, the issues related to in-situ doping of silicon carbide (SiC) semiconductor during epitaxial growth are reviewed. Some of these issues can find solution by using an original approach called vapour-liquid-solid (VLS) mechanism. In this technique, the SiC seed is covered by a Sibased melt and is fed by propane in order to growth the epitaxial film. Using Al-Si melts and temperatures as low as 1100°C, very high p type doping was demonstrated, with a record value of 1.1021 at.cm-3. It leads to very low contact resistivity and even to metallic behaviour of the SiC deposit even at low temperature. Using Ge-Si melts, non intentionally low doped n type layers are grown. By forming Si-containing liquid droplets on a SiC seed, one can extrapolate this VLS growth to selective epitaxial growth (SEG). Such approach was successfully applied for both Al and Ge-based systems in order to form p+ and n doped areas respectively.