9,984 research outputs found
Preparation and characterization of Pb(Zr,Ti)O-3 films deposited on Pt/RuO2 hybrid electrode for ferroelectric random access memory devices
No full textPolycrystalline Pb(Zr,Ti)O-3 (PZT) films were fabricated at a low temperature of 450 degreesC by the electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECR PECVD) method. Stoichiometric PZT films with the pure perovskite phase could be obtained over a wider range of deposition conditions on Pt/RuO2 hybrid electrodes than on RuO2 electrodes. PZT capacitors fabricated on Pt/RuO2 hybrid electrodes showed low leakage current and superior polarization characteristics compared with those on RuO2 electrodes. PZT capacitors fabricated on Pt/RuO2 were not as fatigue-free as those on RuO2 but had higher resistance to fatigue than those on Pt. The introduction of a PbTiO3 buffer layer prior to PZT film deposition on Pt/RuO2 improved the fatigue characteristics by suppressing the formation of nonstoichiometric interfacial layers. Good leakage current property (J: 5.8 x 10(-7) A/cm(2) at 200 kV/cm) and fatigue characteristic (P* - P-boolean AND: 9% drop after 4 x 10(9) fatigue cycles) could be obtained for the 110-run-thick PZT film using Pt/RuO2 hybrid top and bottom electrodes. This electrode structure is thought to be promising for use as a capacitor of high-density ferroelectric random access memory (FRAM) devices. The fatigue model that can explain the fatigue characteristics of PECVD-PZT capacitors with various hybrid electrode configurations is also suggested.The Consortium of Semiconductor Advanced Research (COSAR) as project No. 00-B6-C0-00-09-00-01
Characterization of Pb(Zr, Ti)O-3 thin films fabricated by plasma enhanced chemical vapor deposition on Ir-based electrodes
No full textStructural and electrical characteristics of Pb(Zr, Ti)O-3 (PZT) ferroelectric thin films deposited on various Ir-based electrodes (Ir, IrO2, and Pt/IrO2,) using electron cyclotron resonance plasma enhanced chemical vapor deposition were investigated. On the Ir electrode, stoichiometric PZT films with pure perovskite phase could be obtained over a very wide range of processing conditions. However, PZT films prepared on the IrO2 electrode contain a large amount of PbOx phases and exhibited high Pb-excess composition. The deposition characteristics were dependent on the behavior of PbO molecules on the electrode surface. The PZT thin film capacitors prepared on the Ir bottom electrode showed different electrical properties depending on top electrode materials. The PZT capacitors with Ir, IrO2, and Pt top electrodes showed good leakage current characteristics, whereas those with the Ru top electrode showed a very high leakage current density. The PZT capacitor exhibited the best fatigue endurance with an IrO2 top electrode. An Ir top electrode provided better fatigue endurance than a Pt top electrode. The PZT capacitor with an Ir-based electrode is thought to be attractive for the application to ferroelectric random access memory devices because of its wide processing window for a high-quality ferroelectric film and good polarization, fatigue, and leakage current characteristics. (C) 2002 American Vacuum Society.This research was supported by the Consortium of Semiconductor
Advanced Research ~COSAR! as project No. 00-
B6-C0-00-09-00-01
Round pinholes in indium-tin-oxide thin films on the glass substrates: a Taguchi method analysis and theoretical approach to their origins
No full textThe origin of the round pinholes, ranging 30-70 mum in diameter, in indium-tin-oxide (ITO) thin films on the glass substrates were investigated. It has been found that the round pinholes in ITO thin films might arise from the tiny particles and organics, adsorbed onto the residual water of imperfectly pre-dried glass substrates at the pre-drying bath. The tiny particles and organics on the glass substrates might cause to weaken the adhesive powers between the ITO thin films and the glass substrates, finally resulting in the round pinholes at the photopatterning process. By Taguchi methods, it was revealed that the generation of the round pinholes in ITO thin films was directly related to the temperature and the amount of heat supply at the pre-drying bath. A simplified mechanism on the formation of the round pinholes in ITO thin films is proposed and verified. (C) 2003 Elsevier Ltd. All rights reserved
Electron scattering mechanisms in indium-tin-oxide thin films: grain boundary and ionized impurity scattering
No full textCarrier concentrations and mobilities of indium-tin-oxide (ITO) thin films by DC magnetron sputtering at the various process temperatures were measured using the Hall Technique. The relationship between the carrier concentrations and mobilities had two distinct regions: (i) roughly up to the process temperatures of 300degreesC with carrier concentrations of 9.0 x 10(20)/cm(3), both carrier concentrations and mobilities increased together with the process temperatures; (ii) above the process temperature of 300degreesC with carrier concentrations over 9.0 x 10(20)/cm(3), the carrier mobilities decreased as the carrier concentrations increased with the process temperatures. These distinct relationship between carrier concentrations and mobilities were due to the transition of the dominant electron scattering mechanisms in ITO thin films with the process temperatures. At low process temperatures, the crystallinities were low and the grain boundary scattering was dominant. However, at high process temperatures, ITO thin films were highly crystallized and the ionized impurity scattering was dominant. The overall characterizations related to the carrier concentrations and mobilities were also performed using an X-ray diffractometer and a scanning electron microscope. (C) 2004 Elsevier Ltd. All rights reserved
Temporal variations in the size and composition of Formosan leaf-nosed bat (Hipposideros terasensis) colonies in central Taiwan.
No full textEstimating the catch of offshore fisheries for the fishing vessels above 20 tin Taiwan, 1998.
No full textO-17 NUCLEAR MAGNETIC-RESONANCE SPECTROSCOPIC STUDIES OF CARBONMONOXY HEMOPROTEINS
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The evolution of the structural, electrical and optical properties in indium-tin-oxide thin film on glass substrate by DC reactive magnetron sputtering
No full textThe evolution of the structural, electrical and optical properties in indium-tin-oxide (ITO) thin film on glass substrate prepared by DC reactive magnetron sputtering was investigated. The variation of the structural, electrical and optical properties could be largely divided into two regions of (i) the initial region I roughly up to the critical film thickness of 50 mn and (ii) the stable region II above the critical thickness. As the film thickness grew, X-ray diffraction (XRD) peak intensities of both (2 2 2) and (4 0 0) planes increased continuously and the film morphology became clear. The peak intensity ratio of I-122/I-400 decreased gradually with the thickness, implying a preferred orientation along the (400) plane at a higher thickness. In the region II over the critical film thickness of 50 nm, where the structural evolution was clearly observable, the carrier density also increased over 9.0 x 1020/cm(3) and the specific resistivity was lower than 140 mu Omega cm. (c) 2006 Elsevier Ltd. All rights reserved
A Minimized Hardware Architecture of Fast Phong Shader Using Taylor Series Approximation in 3D Graphics
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