1,720,959 research outputs found
Platinum hillocks in Pt/Ti film stacks deposited on thermally oxidized Si substrate
No full textThe stress dependence of platinum hillock formation during post thermal cycling was investigated in Pt/Ti electrode stacks. Annealing temperatures were varied from room temperature (RT) to 650 degreesC. High compressive stress was generated during electrode annealing by the Ti diffusion into the platinum layer followed by oxidation in the platinum grain boundaries. The compressive stress was the major driving force for the hillock formation on the platinum surface, Thus. the Ti glue layer was oxidized before platinum deposition to reduce the Ti diffusion. The Pt/TiOx electrode stack retained its smooth platinum surface after the electrode annealing of 650 degreesC for 30 min in O-2. The Pt/TiOx interface remained flat even after the ferroelectric annealing at 800 degreesC, which was performed after SrBi2Ta2O9, (SBT) deposition. Moreover, the remanent polarization (2P(r),) of the SBT capacitor was increased to 17 muC/cm(2) on the Pt/TiOx electrode stack, up from 13 muC/cm(2), which was the value on the Pt/Ti electrode stack
Interfacial layer properties of HfO2 films formed by plasma-enhanced atomic layer deposition on silicon
No full textThe interfacial oxide layers, generated on Si substrates during the initial stage of HfO2 atomic layer deposition (ALD), have been investigated depending on the oxygen reactants, oxygen plasma and water. In the plasma-enhanced ALD (PEALD) using oxygen plasma, a 2-nm-thick interfacial layer, which was intermixed with Hf-Si-O and SiO2 having a dielectric constant (k) of 6.5, was formed, while water made a 1.5-nm-thick interfacial layer composed mainly of SiO2. Additionally, by utilizing oxygen plasma, the k of the HfO2 film itself was increased up to 22.2 resulting in a higher effective k, and a much lower leakage current density was also obtained. (c) 2006 The Electrochemical Society.This work was supported by the project of Brain Korea 21(BK21).
Korea Advanced Institute of Science and Technology assisted in meeting the publication costs of this article
Thermal stability and electrical properties of SrBi2Ta2-xNbxO9/IrOx capacitors with Pt top electrode
No full textBoth SrBi2Ta2-xNbxO9 (SBTN) film and IrOx electrode were used for fabricating a capacitor of high-density ferroelectric random access memory. IrOx was deposited by reactive sputtering, and the spin-on technique was used for coating the SBTN layer. Marked evaporation was observed in 2000-Angstrom -thick IrOx film after electrode annealing at temperatures above 700 degreesC. The evaporation was caused by the reduction of IrOx to metallic iridium. However, SBTN/IrOx stack remained stable even after annealing up to 800 degreesC. Ferroelectric crystallization annealing during the integration was performed at 650 degreesC for the application of stacked capacitor architecture. Thus, the Pt/SBTN/IrOx capacitor could be fabricated up to metallization without damaging the microstructure, The switching polarization was about 10 muC/cm(2) at the 2.4 mum x 3.7 mum x 256 ea array capacitor after metallization and the leakage current density was about 4 x 10(-7) A/cm(2) The contact resistance of the SBTN/IrOx/Ir/TiN/plug was about 1500 Omega /plug at the contact size of phi 0.30 mum
Stacked Pt/SrBi2Ta2-xNbxO9/Pt/IrOx/Ir capacitor on poly plug
No full textA Pt/SrBi2Ta2-xNbxO9(SBTN)/Pt/IrOx/Ir capacitor was successfully fabricated up to the stage of metal-1 etching process on a polysilicon plug for mega-bit ferroelectric random access memory. The integration processes include the chemical-mechanical polishing technique, buried TiN barrier structure and electrode technologies for high thermal stability, and a low-temperature process for SBTN film. The thickness of the iridium layer was the most important factor in controlling the contact resistance of the plug. The Pt thickness also affected the contact resistance of the plug. The best contact resistance of the plug was about 2.0 kOhm/plug at the maximum process temperature of 750degreesC for 3 min in oxygen ambient at the contact site of phi0.30 mum. Hysteresis curves of the SBTN capacitor were obtained after the metal-1 etching process. The capacitor size dependency of the polarization was not observed in the range of 0.30-25 mum(2) and the values of the sensing polarization were about 10 muC/cm(2) at the applied voltage of 3 V. In addition, the capacitor exhibited no fatigue loss up to 5 x 1010 cycles at the,witching voltage of 3 V
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Composition and electrical properties of metallic Ru thin films deposited using Ru(C6H6)(C6H8) precursor
No full textMetallic ruthenium films were prepared by metalorganic chemical vapor deposition (CVD) using a new precursor named (eta(6)-benzene)(eta(4)-1,3-cyclohexadiene)ruthenium (Ru(C6H6)C6H8)) in Ar atmosphere, and the absolute composition and electrical properties were investigated. The absolute composition including hydrogen was determined by means of the elastic recoil detection time of flight (ERD-TOF). It was found that carbon contents in the films markedly decreased when tetrahydrofuran (THF) was supplied with the precursor during deposition. The variation in carbon content could be interpreted by the formation of hydrocarbon compounds as well as the formation of carbon oxide, resulting from the reaction between carbon and THF. In particular, Ru films contained hydrogen that originated in the hydrogen atoms in the precursor and was involved in the CVD process due to the catalytic effect of ruthenium on hydrocarbon and hydrogen. It was shown that grain size, among several other factors strongly affected the electrical properties of ruthenium films. [DOI: 10.1143/JJAP.41.6852]Consortium of Semiconductor Advanced
Research
Applied Superconductivity Technology R&D Progra
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