1,720,963 research outputs found
Preparation of a-SiNx thin film with low hydrogen content by inductively coupled plasma enhanced chemical vapor deposition
No full textAmorphous silicon nitride (a-SiNx) thin films are deposited at low temperature by remote-type inductively coupled plasma enhanced chemical vapor deposition (ICP-CVD) using N-2/SiH4 gases as reactant gases to obtain low hydrogen content in the films. Refractive index, deposition rate, stoichiometry, hydrogen content, and hydrogen configuration in the films are analyzed with the varation of deposition parameters. As RF power and N-2 flow rate increase, refractive index decreases due to the decrease of Si/N ratio, total hydrogen content is constant with N-H changing hydrogen bond configurations (Si-H, N-H) reversely. However, as substrate temperature increases, refractive index increases due to the reduction of Si/N ratio, and total hydrogen content as well as both hydrogen bond configurations (Si-PI, N-H) decrease. In remote-type ICP-CVD using N-2/SiH4 gases, N rich a-SiNx films with low refractive index and density are deposited due to efficient dissociation of N-2 gas by high density plasma, and hydrogen content in the films is greatly reduced.This work was supported by Ministry of Education through Interuniversity Semiconductor Research Center(ISRC 96-E-4021)in Seoul National University.
Korea Advanced Institute of Science and Technology assisted in meeting the publication costs of this article
Effects of NH3 Carrier Gas on the Deposition and Electrical Characterics of SrTiO3 Films Grown by ECR Plasma Assisted MOCVD
No full text
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
A comparative study on the properties of TiN films prepared by chemical vapor deposition enhanced by rf plasma and by electron cyclotron resonance plasma
No full textTiN thin films were prepared by both r.f. plasma enhanced chemical vapor deposition (r.f.-PECVD) and electron cyclotron resonance plasma enhanced chemical vapor deposition (ECR-PECVD) using TiCl4, N-2 and H-2 as the reactants at various deposition temperatures. The effects of deposition temperature on the compositional ratio [N]/[Ti], impurity content, crystallinity, lattice parameter, grain size, deposition rate, resistivity and step coverage were studied. TiN films prepared by ECR-PECVD were highly crystallized at a low temperature of 350 degrees C, while TiN films prepared by r.f.-PECVD began to show obvious crystallinity above 500 degrees C. TiN films deposited by ECR-PECVD at lower temperatures had lower impurity contents and lower resistivity than those deposited by r.f.-PECVD.This research was performed within the 'Studies on Advanced Basic Technology' for future microelectronics project of Korean Electronics and Telecommunications
Research Institute
Composition, oxidation, and optical properties of fluorinated silicon nitride film by inductively coupled plasma enhanced chemical vapor deposition
No full textAmorphous fluorinated silicon nitride films have been deposited with the variation of NF3 flow rate using SiH4, N-2, Ar, and NF3 gases by inductively coupled plasma enhanced chemical vapor deposition for the first time, and the absolute composition, oxidation mechanism, and optical properties were investigated. The absolute composition including hydrogen was performed by means of elastic recoil detection time of flight, It was found that the oxygen and fluorine contents in the film dramatically increased, but the hydrogen content decreased to below 4 at.% as the NF3 flow rate increased. The oxidation mechanism could be explained in terms of the incorporation of the activated residual oxygen species in the chamber into the film with unstable open structure by the fluorine-added plasma. It was shown that the density and optical properties such as refractive index, absorption coefficient, and optical energy gap depended on the film composition. The variations of the above properties for fluorinated silicon nitride film could be interpreted by the contents of fluorine and oxygen with high electronegativity.The authors thank Dr. J. K. Kim in Korea Institute
of Geology, Mining and Materials for valuable assistance
in the ERD-TOF measurement. This study was
supported by the academic research fund of Ministry of
Education, Republic of Korea, through Inter-University
Semiconductor Research Center (ISRC 97-E-1024) in
Seoul National University
Formation identification of Y2BaCuO5 and BaCeO3 in MOCVD-processed YBCO films with Ce doping
No full textThe influence of nanosized secondary particles, such as those produced via rare-earth doping for example, on magnetic-field-induced flux motion in YBa2Cu3O7-delta (YBCO)-coated conductors has been investigated. In this study, we investigated the influence of Ce doping on nanosized secondary phase formation in YBCO films. Ce-doped YBCO films on single SrTiO3 crystals were prepared viametal-organic chemical vapor deposition (MOCVD). For the first time, a Y2BaCuO5 (Y211) secondary phase was observed in the Ce-doped YBCO film, while the pure YBCO film contained only a Y2O3 secondary phase. As Ce doping concentration increased to 3 wt%, a BaCeO3 secondary phase developed. This was due to the low solubility limit of Ce for Y in the MOCVD YBCO film. Additionally, outgrowths on the Ce-doped YBCO film surfaces and defect structures, such as a-axis grains, were examined
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
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