Papers by Keyword: Thermal Oxidation

Abstract: This study investigates the effects of lower pressure and chlorine gas added oxidation on the GOI during the SiC MOSFET GOX process. For structural comparison, analyses were conducted using Dynamic SIMS and TOF-SIMS. Notable differences in the uniformity of silicon concentration within the oxide layer were observed under various GOX conditions. To evaluate the impact of these differences on the characteristics of SiC MOSFETs, Q_BD results were compared. To enhance the reliability of the findings, DOE evaluations of GOX were performed across multiple products. The experimental results indicated that the SiC MOSFET wafers subjected to chlorine oxidation exhibited improved Q_BD performance compared to other conditions.

Abstract: This study presents a novel work on the synthesis of Mn-doped ZnO microstructures via thermal oxidation of Zn metal sheet in the presence of MnCl₂ mist. Structural analysis via XRD shows the growth of ZnO particles for the sample oxidized in water vapor while simonkolleite and ZnO both formed for the samples oxidized with MnCl₂. Shifting of ZnO diffraction peaks suggests incorporation of impurity atom within the crystal lattice of the material. SEM images show layered formation of simonkolleite at the bottom and ZnO particles at the top of the substrate. At increasing MnCl₂ concentration, the growth of ZnO particles and simonkolleite phases were hampered which is attributed to the hindering of the oxidation process by the presence of Cl^- anion.

Abstract: Thermal oxidation of 4H-SiC to grow native-oxide SiO₂ is always followed by the generation of crystal defects and lattice distortion. We studied the relaxation of this distorted lattice on thermally-oxidized 4H-SiC surface by performing annealing process with several conditions. The surface distortion could be relaxed partially by annealing under argon, nitrogen monoxide, and H₂O gases, confirmed by in-plane X-ray diffractometer. This surface relaxation is possibly induced by the release of oxygen-related defects, as confirmed by thermal desorption analysis. The surface distortion caused by thermal oxidation is due to the existence of oxygen in 4H-SiC lattice, while the relaxation is caused by the migration of the oxygen-related defect structure, and emitted from 4H-SiC surface region as CO molecule.

Abstract: Magnesium and its alloy have good characteristics for implant materials. Increasing these characteristics is needed to be an excellent material. The objective of this research is to investigate the magnesium alloy AZ31 (Al: 3.07%; Zn: 1.05%) characteristics affected by thermal oxidation temperature. Investigated characteristics in this study were hardness, corrosion resistance, and microstructure. The temperature variations of thermal oxidation were 100, 200, 300, 400 °С. The Vickers micro-hardness decreased with increasing of thermal oxidation temperature and the as-received of Mg alloy had the highest Vickers micro-hardness. The lowest corrosion resistance occurred at 200 °С of thermal oxidation temperature but this corrosion resistant was higher than that at the as-received material. The microstructures of Mg alloy were looked cracked in their grains at the thermal oxidation temperature over than 200 °С. The cracks increased by increasing of the thermal oxidation temperature.

Abstract: In this research work, brass (Cu - 37.2 wt% Zn) and Cu (99.9 wt%) wires having diameters of 200 μm were thermally oxidized in N₂ containing 5% O₂, at a flow rate of 200 sccm and in the ambient atmosphere respectively, to support the growth of nanowires. The oxidation temperature was varied from 300 to 600 °C and the as-grown nanowires were characterized by field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray (EDX) spectroscope, and transmission electron microscope (TEM). Results show that ZnO and CuO nanowires are formed on brass and Cu wires, respectively. The ZnO nanowires are branched and CuO nanowires are straight with tapered morphology. ZnO nanowires having hexagonal wurtzite structure grow along the <1 1 0> directions whereas, CuO nanowires have monoclinic structure. A diffusion based stress induced model is proposed to explain the growth mechanism of the nanowires. Thermal oxidation process is a suitable platform for synthesizing ZnO and CuO nanowires, which can be used in in-situ device fabrication.

Abstract: In this work, the interface between 4H-SiC and thermally grown SiO₂ is studied using low energy muon spin rotation (LE-μSR) spectroscopy. Samples oxidized at 1300 °C were annealed in NO or Ar ambience and the effect of the ambience and the annealing temperature on the near interface region is studied in a depth resolved manner. NO-annealing is expected to passivate the defects, resulting in reduction of interface traps, which is confirmed by electrical characterization. Introduction of N during annealing, to the SiC matrix, results in a thin, carrier rich region close to the interface leading to an increase in the diamagnetic asymmetry. Annealing in an inert environment (Ar) seems to have much lesser impact on the electrical signal, however the μSR shows a reduced paramagnetic asymmetry, indicating a narrow region of low mobility at the interface.

Abstract: In this work, we study the impact of the dose rate on the electrical properties of aluminum (p-body, p⁺-body-contact) and phosphorous (n-source/drain) implanted 4H-SiC. We find no significant differences for dose rates ranging from 1×10¹¹ cm^-2s^-1 to 2−7×10¹² cm^-2s^-1. AFM scans across implanted and non-implanted regions after thermal oxidation and subsequent oxide etching reveal a clear dependence of the oxidation rate on the conduction type and doping concentration. In addition, we observe an increasing (decreasing) oxidation rate for increasing doping concentrations of the n-type (p-type) ion implanted areas.

Abstract: By the method of thermal oxidation of n-type CuInSe2 crystals, n - n+ structures with a maximum absolute current photosensitivity of up to 10 mA / W were obtained at low rectification and no-load photovoltage. The used modes of thermal oxidation led to the formation of n-type layers on the surface of the n-CuInSe2 plates, the resistivity of which is 2-2.5 times higher concerning the initial substance. Measurements of the stationary current-voltage characteristics have shown that the structures obtained have a slight rectification K. All the structures obtained exhibit photosensitivity, which dominates when illuminated from the side of the layer in the spectral region of about 1 eV. The optimization of the process can reveal the technological possibilities of a significant improvement in the rectifying properties of isotypic structures based on CuInSe2.

Abstract: The article aims to investigate the feasibility of oxidation protection imparted to C-103 Nb-based alloy by fused slurry silicide coating of R512E (60Si20Fe20Cr) carried out at lower temperature (1200 °C) for higher dwell time i.e. 12 hours. The findings reveal that the coating treated can impart sufficient oxidation resistance the alloy, which may withstand the desired application conditions wherein oxidation protection for smaller time period is needed. Moreover, this treatment is not found to deteriorate other mechanical properties of the alloy in 'As coated' condition.

Abstract: In this paper, visible-light-active monoclinic WO₃ powders were synthesized by thermal oxidation of W powders at 200 – 1000 °C in air atmosphere. Morphology and crystal structure of annealed W powders were characterized by Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD), respectively. Based on SEM and XRD results, a spherical orthorhombic-W₃O₈ obtained at 200 °C was transformed into a dendritic monoclinic WO₂ + tetragonal WO₃ + monoclinic WO₃ structures at 400 °C accompanied by a color transition from grey into green. At 600 °C, yellow monoclinic WO₃ + monoclinic WO_2.96 powder was produced that ascribed to oxygen vacancies. Photocatalytic activity of annealed W powders demonstrated 70.7% Cr (VI) removal after 150 min on sample annealed at 1000 °C. This ascribed to high photoactivity of monoclinic WO₃. Nevertheless, the dendritic monoclinic WO₂ + tetragonal WO₃ + monoclinic WO₃ obtained at 400 °C exhibited the lowest Cr (VI) photoreduction i.e. 45.2% implies less photoactive monoclinic WO₂ and sluggish electron transport at oxide-oxide interfaces.