Longer Annealing Time Research Articles

Self-seeding effects on the transition between the low and the high-Tcphase in samples of the Bi-Pb-Sr-Ca-Cu-O system by solid phase reaction

Abstract Samples of the superconducting Bi-Pb-Sr-Ca-Cu-O system were prepared in the form of film, powder or sintered mass by rapid quenching or solid phase reaction. In samples prepared by repetitive pulverizing-mixing and annealing-sintering, a “self-seeding effect” (solid-in-solid epitaxy) was discovered. In comparison with the film sample, the annealing time for obtaining the high-Tc phase was shortened greatly in the samples by the above repetitive processing. Longer annealing times made the amount of the phase decrease.

Influence of annealing in N2 atmosphere on the properties of Bi-system 2223 phase

The influence of annealing in N 2 atmosphere on the superconductivity and normal states of a series Bi-system 2223 phase samples with high quality were studied by x-ray diffraction, thermal analysis and resistivity determination. It was discovered as the annealing time was increased, the critical temperature of the sample increased and the resistivity decreased. There was an optimum time for annealing. As the annealing time was longer than this optimum time, the converse result was obtained, namely, the increase in annealing time made the Tc decrease and resistivity increase. The experiment also showed that this effect was reversible. The Tc was suppressed by longer annealing time in N 2, but constrictive annealing in O 2, the original state could be recovered. The difference between these and some former results is discussed. Analyzing the results carefully, the relationship between Tc and resistivity, then the Tc and carrier concentration is well established.

Self-seeding effects on the transition between the low and high-TC phases in the BiPbSrCaCuO system

Abstract Samples of superconducting BiPbSrCaCuO system were prepared in the form of films, powders or sintered buttons by rapid-quenching. As a result of repetitive pulverizing-mixing and annealing-sintering, “self-seeding effect” (solid-in-solid epitaxy) occurs in these samples. In comparison with the films, the annealing time required for the high-TC phase was shortened greatly in the case of the bulk-samples. The longer annealing time made the amount of the high-Tc phase decrease.

Stabilization of the 108 K superconducting phase in the Bi0.7Pb0.3SrCaCu1.8O y system

Samples having the nominal composition Bi0.7Pb0.3SrCaCu1.8O y , were prepared by a solid-state reaction and characterized by energy-dispersive x-ray microanalysis, resistivity measurements, and magnetically modulated microwave absorption (MAMMA). Longer annealing times resulted in more homogeneous samples having a single superconducting transition to zero resistance at 108 and 105 K at 0.1 and 1 mA, respectively. The MAMMA measurements clearly show differences in sample homogeneity with different annealing times.

Electrical Characterization of Metal Contacts on Diamond Thin Films

ABSTRACTPolycrystalline boron-doped diamond thin films were prepared by microwave-enhanced plasma-assisted chemical vapor deposition. Ti, V, Ta, Nb, Al, Mo and W contacts were prepared by physical vapor deposition and their behavior was studied as a function of the annealing temperature, atmosphere and duration. For Ti contacts, short heat treatments (less than 60 minutes) at 500 °C under argon atmosphere were found to make ohmic contacts for applied voltages up to 50 V. Longer annealing times, more reactive atmospheres, and higher temperatures degraded the contact characteristics. In order to obtain a more complete picture of the interface structure, the capacitance-voltage characteristics and the impedance spectra of the systems were measured between 10 K and 1000 K. The interface contribution to the overall dielectric behavior of the system shows much shallower depletion widths in Ti-diamond (ohmic) contacts than with the non-linear Nb and Ta contacts. The higher values of the contact resistance and the shallower depletion width with Ti can be explained in terms of formation of a thin carbide-like region at the metalsemiconductor interface. The space-charge region width as well as the distribution of localized states in the band gap were also determined. The effect of the microstructure on the electrical properties of the systems is discussed in comparison with the behavior of metal-contacts on single-crystal diamonds.

Effect of n +-polycrystalline silicon gate rapid thermal annealing on the electrical properties of the gate oxide

The application of the rapid thermal annealing (RTA) technique as a high temperature step needed to activate the dopant in polycrystalline silicon gates and the effect of this anneal on the electrical properties of the underlying gate oxide were studied for RTA times ranging from 1 to 100 s and temperatures from 950 to 1050°C in an N 2 ambient. A time of 10 s was found to result in the best I- V and C- V characteristics of the metal-oxide-semiconductor structures for the entire temperature range studied. An increase in the RTA temperature causes increased electron trapping during avalanche injection. Longer annealing times at a constant temperature also resulted in an increase in the density of deep electron traps. Standard furnace annealing was significantly better than RTA only from the point of view of the resistance of the annealed structures to the generation of interface states on high field electron injection.

The effect of Anti-Phase Domain Size on the Ductility of a Rapidly Solidified Ni3Al-Cr Alloy

ABSTRACTTensile tests on splat-quenched Ni3Al-Cr alloys showed a sharp decrease in ductility with long-time annealing. The growth of the initially very-fine size anti-phase domains showed a tenuous correlation with ductility up to a critical size, where ductility was lost. The grain size was relatively unaffected by these annealing treatments, but the grain-boundary curvature decreased, implying less toughness. An important observation was that for the longest annealing time a chromium-rich precipitate formed, which our data indicate could be a boride. Miniaturized tensile tests were performed on samples which were all obtained from the same splat-quenched foil, and the various domain sizes were controlled by subsequent annealing treatments.

The effects of oxygen dose on the formation of buried oxide silicon-on-insulator

The effects of the oxygen dose on the microstructure and the dielectric properties of the buried oxide in oxygen implanted silicon-on-insulator (SOI) structures have been studied. Cross-sectional transmission electron microscopy analyses show that the density of oxygen precipitates at the silicon/buried-oxide interface increases with a decreasing oxygen dose when identical annealing processes are employed. Annealing studies reveal that 1275 °C anneals annihilate the oxygen precipitates. A longer annealing time is required to achieve an oxygen-precipitate-free silicon layer in an SOI substrate implanted with a lower oxygen dose. The inverse relationship between oxygen content in the silicon film and oxygen dose is attributed to the redistribution of oxygen during implantation. In the oxygen dose range studied, the thickness and the breakdown voltage of the buried oxide layer increase with increasing oxygen dose. Higher postimplant annealing temperature improves the isolation properties of the buried oxide layer.

Rapid thermal annealing of 200°C mercury implants into InP

Elevated-temperature (200°C) implants of 1014 and 1015 Hg ions cm−2 at 100keV have been successfully activated by rapid thermal annealing at temperatures of 750–850°C using a novel dual layer of Si3N4 and AlN as an encapsulant. P-type activity was found for all samples, yielding maximum hole concentrations of approximately HV = 8 × 1017 cm−3 and mobilities of 100 cm2/Vs. Sheet carrier concentrations were found to increase with temperature for 60s anneals, giving a value of 0.8 eV for the ‘activation energy’ of Hg implants in InP. Longer annealing times resulted in a degradation of the encapsulant and a corresponding reduction in electrical properties.

Einfluß einer Auslagerung unter Schutzgas bei 800 bis 1000 °C auf die mechanischen Eigenschaften des Werkstofftyps X 10 NiCrAlTi 32 20

AbstractVersuchsdurchführung unter Argonatmosphäre bei 800, 900 und 1000 °C – mechanische Kennwerte bei Raumtemperatur in Abhängigkeit von Prüftemperatur und Auslagerzeit – licht‐ und elektronenoptische Untersuchung des Mikrogefüges – Zuordnung mechanischer Kennwerte und Mikrogefüge.

Recrystallization of cast polycrystalline silicon

The polycrystalline silicon used in this study was obtained by oriented solidification. It was deformed in tension at 1050 °C and then annealed at 1396 °C. The variation in the recrystallized fraction as a function of the initial deformation and of the annealing time was studied and the results obtained are analogous to the behaviour of metals, with the added requirements of a higher temperature and a longer annealing time. Recrystallization leads to larger grains of different morphologies and better crystalline perfection.

Impact and yield properties of polycarbonate as a function of strain rate, molecular weight, thermal history, and temperature

AbstractA study has been made on the impact and yield properties of polycarbonates from two manufacturers as a function of strain rate, melt flow rate, notch radius, thermal history, and test temperature. The yield stress increases with the strain rate and annealing time in exactly the way predicted by a recently proposed theory on nonlinear viscoelasticity of glassy polymers. The critical molecular weight for the transition from a ductile to a brittle break increased at higher rate of strain and also with the longer annealing times.