Papers by Keyword: Annealing

Abstract: Most of the advanced Zr-based alloys contain Nb for improving the corrosion resistance. However, the Nb effect on the corrosion behavior of Zr alloys has not been established. For developing fuel cladding materials, it is essential to investigate the effect of the Nb-content and annealing conditions after beta quenching on the microstructure and the corrosion of Zr-xNb alloys. In this study, a systematic investigation to obtain the optimized annealing condition and Nb content were performed for Zr-xNb alloys (x = 0.1~2.0 wt.%). The corrosion resistance of 0.1 and 0.2 wt.% Nb alloys where Nb existed in an equilibrium soluble state in the matrix was excellent in the quenched and annealed conditions. For the high Nb-containing alloys, the corrosion rates were very sensitive to the annealing condition, and it took about 50 hours at 570
to reach the corrosion rates comparable to those of the low Nb wt.% alloys. The corrosion resistance was closely related to the stabilization of the tetragonal ZrO2 and the columnar oxide structure when the Nb concentration in the matrix was reduced to the equilibrium soluble limit.

Abstract: The effects of annealing temperature and annealing time on mechanical properties of cold drawn pearlitic steel wires containing 0.84wt% of silicon were investigated. Annealing treatment was performed on cold drawn steel wires for the temperature range of 200°C to 450°C with the different annealing time of 30sec, 1min, 15min and 1hr. The increase of tensile strength at the low annealing temperatures would be related with strain ageing behavior, while the decrease of tensile strength at the high annealing temperature is due to the spheroidization of cementite plates and the occurrence of recovery of the lamellar ferrite in the pearlite.

Abstract: A novel flexible polymer was used for the new generation display panel, which was prepared by thermal annealing treatments. Atomic force microscope (AFM) and visible spectroscopy were employed to measure the surface roughness and the optical transparency of the substrates. Mechanical cycles bending were carried on the flexible substrates in this study. Surface morphology of the substrates after bending was observed by scanning electron microscope (SEM). The performances of the OLED device were compared for the samples with and without cycles bending.

Abstract: The structure and properties of in situ Cu-Nb composites have been studied by the methods of TEM and SEM, X-ray analysis and mechanical testing. The evolution of Nb filaments structure at drawing and the effect of annealing and doping with Zr on the composites structure and texture have been investigated. Sharp fibre texture with <110>Nb develops in the ribbon-shaped Nb filaments, while the Cu matrix possesses a two-component fibre texture, <111>Cu and <100>Cu, appreciably affected by annealing. Annealing results in softening due to Nb filaments coagulation. In Zr doped composites two types of ZrO2 particles are observed, dispersed and coarse ones. The former result in the dispersion strengthening, while the latter may cause embrittlement.

Abstract: The impact of high temperature annealing using graphite encapsulation (formed by baking photoresist) on the electrical properties of Ni Schottky diodes formed on the annealed surfaces is studied. The surface morphology is also characterized by atomic force microscopy (AFM). Annealing for 10 minutes at temperatures up to 1800 °C with graphite encapsulation actually reduces the high-current ideality factor of the diodes while raising the current-voltage barrier height (linearly extrapolated to unity ideality factor) from 1.453 V to 1.67-1.73 V. Excess leakage current occurs only in a subset of diodes, which are believed to be affected by extended defects. The AFM images show no significant surface roughening, and the graphite can be removed after processing. This encapsulation method is found to be highly effective in preserving the electronic properties of the surface during high temperature annealing.

Abstract: 4H-SiC samples implanted at 600°C with 1020 cm-3 of B or B and C to a depth of ~0.5 μm, capped with (BN/AlN), and annealed at temperatures ranging from 1400°C – 1700°C were studied using variable temperature cathodoluminescence. New emission lines, which may be associated with stacking faults, were observed in the samples co-implanted with B and C, but not in the samples implanted only with B. For both the B and B and C co-implanted samples, the intensity of the line near 3.0 eV decreases with increasing annealing temperature, TA, and this line is not observed after annealing at 1700°C. The D1 defect related emission lines are observed in the luminescence spectra of all samples and their relative intensities seem to vary with the implantation-annealing schedule and excitation conditions.

Abstract: It is investigated whether the homogeneous depth profiles of epitaxially doped B or Al are changed or preserved by implantation of various implanted species and annealing processes. We have found a strong decrease in the atomic B concentration in epitaxially B-doped layers after implantation of N+, Al+, and P+ and subsequent annealing at 1700 °C. On the other hand, the Al profiles in epitaxially Al-doped layers are preserved after the same processes.

Abstract: Al2O3 has been grown by Atomic Layer Chemical Vapour Deposition (ALCVD) on ntype 4H-SiC using O3 as an oxidant. After post-deposition, annealing at high temperature (1000°C) in Argon atmosphere for different time periods (1h, 2h, 3h) was performed. Bulk and interface properties of the as-grown as well as the annealed films were studied by electrical measurements (CV, IV, DLTS) and Secondary Ion Mass Spectrometry (SIMS) measurements. The electrical measurements show a decreasing shift of the flatband voltage indicating a diminution of the negative oxide charges with increasing annealing time. After annealing at 1000°C for 3h, the flatband voltage shift has decreased to 6V. The SIMS measurements indicate a double interface with a SiOx (x ≤ 2) interlayer in the as-grown samples while only one interface is observed after annealing, leading to improved electrical behavior of the Metal-Oxide-Semiconductor devices.

Abstract: It is generally accepted that the Schottky barrier height (SBH) is affected by the initial band bending at the bare nGaN surface as well as by an additional contribution following metal deposition. In this work the effect of processing used for device fabrication on the surface band bending of bare c-plane nGaN was studied by surface potential electric force microscopy (SP-EFM). An increase of the initial upward band bending from 1.0 ± 0.1eV for the as-grown GaN to 1.9 ± 0.1eV after RTA treatment in N2 ambient was observed. No significant dependence of band bending on N2 or Ar as ambient gas during the RTA treatment was observed. The increase of the initial upward band bending was also confirmed by photoluminescence (PL) measurements. We suggest that the RTA treatment causes a high density of surface states, possibly as a result of high temperature reaction of ambient gas and remnant contamination.

Abstract: Bulk n+-4H-SiC wafers (n=1-2×1019 cm-3) containing annealing-induced stacking faults were examined by Raman scattering. The coupled plasmon-LO mode was observed to shift in a manner consistent with 1018 cm-3 doping in the 4H-SiC. Numerical simulations were performed using a self-consistent Poisson-Schrödinger solver and agree well with the experimental observations of carrier transfer from the 4H-SiC into the 3C-SiC stacking faults. The Raman data also shows that the 3C stacking faults induce a tensile strain on the surrounding 4H-SiC regions.