1,721,202 research outputs found
Current collapse and high-electric-field reliability of unpassivated GaN/AlGaN/GaN HEMTs
No full textLong-term ON-state and OFF-state high-electric-field stress results are presented for unpassivated GaN/AlGaN/GaN high-electron-mobility transistors on SiC substrates. Because of the thin GaN cap. layer, devices show minimal current-collapse effects prior to high-electric-field stress, despite the fact that they are not passivated. Thin comes at the price of a relatively high gate-leakage current. Under the assumption that donor-like electron traps are present within the GaN cap, two-dimensional numerical device simulations provide an explanation for the influence of the GaN cap layer on current collapse and for the correlation between the latter and the gate-leakage current. Both ON-state and OFF-state stresses produce simultaneous current-collapse increase and gate-leakage-current decrease, which can be interpreted to be the result of gate-drain surface degradation and reduced gate electron injection. This study shows that although the thin GaN cap layer is effective in suppressing surface-related dispersion effects in virgin devices, it does not, per se, protect the device from high-electric-field degradation, and it should, to this aim, be adopted in conjunction with other technological solutions like surface passivation, prepassivation surface treatments, and/or field-plate gate
Current collapse and high-electric-field reliability of unpassivated GaN/AlGaN/GaN HEMTs
No full textLong-term ON-state and OFF-state high-electric-field
stress results are presented for unpassivated GaN/AlGaN/GaN
high-electron-mobility transistors on SiC substrates. Because of
the thin GaN cap layer, devices show minimal current-collapse
effects prior to high-electric-field stress, despite the fact that
they are not passivated. This comes at the price of a relatively
high gate-leakage current. Under the assumption that donor-like
electron traps are present within the GaN cap, two-dimensional
numerical device simulations provide an explanation for the influence
of the GaN cap layer on current collapse and for the
correlation between the latter and the gate-leakage current. Both
ON-state and OFF-state stresses produce simultaneous currentcollapse
increase and gate-leakage-current decrease, which can be
interpreted to be the result of gate–drain surface degradation and
reduced gate electron injection. This study shows that although
the thin GaN cap layer is effective in suppressing surface-related
dispersion effects in virgin devices, it does not, per se, protect the
device from high-electric-field degradation, and it should, to this
aim, be adopted in conjunction with other technological solutions
like surface passivation, prepassivation surface treatments, and/or
field-plate gate
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
Influence of gate-leakage current on drain current collapse of unpassivated GaN/AlGaN/GaN high electron mobility transistors
No full textWe report on a correlation between the gate leakage currents and the drain current collapse of
GaN/AlGaN/GaN high electron mobility transistors. Unpassivated devices on intentionally
undoped and doped sSi, 531018 cm−3d heterostructures were investigated. We observed in the
devices that the larger the gate leakage current, the smaller the drain current collapse measured at
50 ns gate-voltage pulse turn on, and this correlation is independent of the doping of the structure.
The correlation holds for two orders of magnitude in the gate-leakage current and up to 15% in drain
current collapse.We believe that the leakage current can modulate trapped surface charge so that the
time constant of the current collapse becomes much faster and dependent on the amount of leakage
current itself
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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