Papers by Keyword: Post Annealing

Abstract: To improve the high resistance and low Breakdown Voltage (BV) of 4H-SiC SBD, the metal annealing process is usually used to to stabilize SBH. We confirmed that post metal annealing after the chip process also stabilizes SBH by the post annealing experiment of applying failure chips (4H-SiC Ti/Al SBD) that have a forward current (I_F) under 1 [A] with high resistance, because of the metal annealing process error. The result of experiments showed that the I_F increment and BV decrement are proportional to the applied temperatures over 450 °C, and the second additional post annealing shows a decrease of I_F and BV. Aluminum and Titanium transformation with post metal annealing made a decrease of SBH, so that the on-resistance is decreased and BV is decreased (in severe cases, the intense post annealing generates Aluminum spiking). From a result of this work, using a suitable post metal annealing, we can improve the I_F of SiC SBD with a high resistance failure from the metal process event.

Abstract: Lanthanum modified lead zirconate titanate (Pb1.1La0.08Zr0.65Ti0.35O3) thin films were fabricated on indium-doped tin oxide (ITO)-coated glass substrate by r.f magnetron sputtering method. The thin films were deposited at 500°C and annealed at various temperature (550~600°C) by rapid thermal processing. The structure and morphology of the films were characterized with X-ray diffraction and atomic force microscopy. The hysteresis loops and fatigue properties of thin films were measured by precision material analyzer. As the annealing temperature increased, the remnant polarization value increased from 10.58 DC/cm2 to 31.35 DC/cm2, coercive field was reduced from 79.906 kV/cm to 60.937 kV/cm. For the switching polarization endurance analysis, the remnant polarization of PLZT thin films annealed at 700°C was decreased 15% after 109 switching cycles using 1MHz square wave form at 5V.

Abstract: In order to improve adhesion strength between TiN coatings and WC-Co substrate, two kinds of interlayer of Co and Ti were pre-deposited before TiN coating process. Thickness and postannealing effects of each interlayer on the adhesion property were investigated through scratch test in this work. Introduction of thin Ti interlayer largely enhanced the adhesion strength between TiN coatings and WC-Co substrate in scratch test. The critical load, Lc2 increased from 64 N without Ti interlayer up to 130N with Ti one of ~ 0.15
thickness. However, post-annealing of TiN/Ti/WCCo system at high temperature of 600 reduced the critical load again. The Ti interlayer caused a deficit of Co content in WC-Co substrate during annealing through diffusion of Co element into Ti interlayer. The reduction of critical load after post-annealing was believed due to diminution in mechanical properties of the substrate derived from the Co deficit in WC-Co substrate. On the other hand, introduction of thin Co interlayer of ~ 0.027
thickness also increased the critical load up to 84 N and improved failure mode, but did not reduce the critical load even after annealing, rather increased it. And, any Co deficit of the substrate was not found after annealing for TiN/Co/WC-Co system.

Abstract: Co/CoO hybrid films are prepared by annealing Co films with various ratio of oxygen of O2/Ar mixture. The nanocomposite film shows a relatively large exchange bias (5.32 kOe) and coercivity (HC-: 6.17 kOe) taken at 80 K when formed by post annealing at 473 K under 3% O2 for 1h. Both are much larger than that of Co/CoO nanocomposite by reactive sputtering with an oxygen partial pressure. Investigation shows that the formation of interface by post annealing is of importance for the large exchange bias and enhanced coercivity. The surface CoO, grain size of CoO and composition may also contribute to magnetic properties of the post annealing film.