125,812 research outputs found
B diffusion in implanted Ni2Si and NiSi layers
No full textB diffusion in implanted Ni2Si and NiSi layers has been studied using secondary ion mass spectrometry, and compared to B redistribution profiles obtained after the reaction of a Ni layer on a B-implanted Si(001) substrate, in same annealing conditions (400-550 degrees C). B diffusion appears faster in Ni2Si than in NiSi. The B solubility limit is larger than 10(21) atom cm(-3) in Ni2Si, while it is similar to 3x10(19) atom cm(-3) in NiSi. The solubility limit found in NiSi is in agreement with the plateau observed in B profiles measured in NiSi after the reaction of Ni on B-implanted Si
Boron clustering in implanted NiSi
No full textB redistribution in a B-implanted polycrystalline NiSi layer has been investigated using atom probe tomography and secondary ion mass spectrometry. The B accumulations observed at the SiO(2)/NiSi interface and in the NiSi bulk are due to B clustering. B cluster formation at these two locations is shown to have a major impact upon the entire B distribution observed after annealing. The formation of B clusters in the NiSi bulk may be due to implantation-related defects. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Interaction of NiSi with dopants for metallic source/drain applications
No full textThis work has a focus on NiSi as a possible metallic contact for aggressively scaled complementary metal oxide semiconductor devices. As the bulk work function of NiSi lies close to the middle of Si bandgap, the Schottky barrier height (SBH) of NiSi is rather large for both electron (similar to 0.65 eV) and hole (similar to 0.45 eV). Different approaches have therefore been intensively investigated in the literature aiming at reducing the effective SBH: dopant segregation (DS), surface passivation (SP), and alloying, in order to improve the carrier injection into the conduction channel of a field-effect transistor. The present work explores DS using B and As for the NiSi/Si contact system. The effects of C and N implantation into Si substrate prior to the NiSi formation are examined, and it is found that the presence of C yields positive effects in helping reduce the effective SBH to 0.1-0.2 eV for both conduction polarities. A combined use of DS or SP with alloying could be considered for more effective control of effective SBH, but an examination of undesired compound formation and its probable consequences is necessary. Furthermore, an analysis of the metal silicides that have a small "intrinsic" SBH reveals that only a very small number of them are of practical interest as most of the silicides require either a high formation temperature or possess a high specific resistivity.</p
Dispelling the Myths Behind First-author Citation Counts
No full textWe 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
The impact of a child's death; An Interpretative Phenomenological Analysis undertaken with five head teachers
No full textAbstract
This research explores with five head teachers their views and experiences of a period when a child was terminally ill and subsequently died when in their school community.
The participants were selected purposively from Derbyshire head teachers who had experienced the death of a pupil in their school community. After interviewing the participants using a semi-structured interview schedule the transcribed interviews provided the data for the research.
The interviews were analysed, using the methodology of Interpretative Phenomenological Analysis, to explore the experiences of each of the participants. Three superordinate themes were identified which were;
Emotions and their management
Interactions with the bereaved family
Interaction with the school community
Additionally, an overarching theme of Elevation was identified.
Each theme is presented and illustrated with abstracts taken from the original data. This is accompanied by interpretation which is also discussed and compared with knowledge from the existing literature.
The research has illustrated the complications that exist for head teachers in managing their emotions and the possibility of these emotions intruding on their personal and family life. It has illustrated the way in which the relationship between the head teacher and the bereaved family changes and how it changes their interactions within the school community.
This research led to the consideration of the influence of the cultural expectation enshrined in the saying, 'De mortuis nil nisi bonum dicendum est' (Of the dead, nothing unless good). Also considered is the behavioural derivative of this saying and how it shapes the responses that head teachers make when managing a school community when a child has died. It also led to the consideration of the implications of the research findings for any support professionals who help schools
Effect of a thin W interlayer on the thermal stability and electrical characteristics of NiSi film
No full textA silicide method was for the first time studied to improve the thermal stability of nickel monosilicide by adding a thin W interlayer within the nickel film. The results show that after rapid thermal annealing (RTA) at temperatures ranging from 650 degrees C to 800 degrees C, the sheet resistance of formed Ni(W)Si samples was lower than that of nickel monosilicide without the interlayer. X-ray diffraction (XRD) and raman spectra results both reveal that only the NiSi phase exists in these samples, but the high resistance NiSi2 phase does not. According to the Gibbs free energy theory, the incorporation of a 7.3 atomic ratio of the W element in the ternary silicide can delay the appearance of the high resistivity NiSi2 phase, and thus enhance the thermal stability of the NiSi film, Fabricated Ni(W)Si/Si Schottky barrier diodes displayed good quality, with the barrier height being located generally between 0.64 eV and 0.66 eV and the ideality factor approaching unity. This further shows that the presence of the W interlayer in nickel silicide is effective in promoting the thermal stability and electrical characteristics of nickel monosilicide. (c) 2005 American Vacuum Society.Engineering, Electrical & ElectronicNanoscience & NanotechnologyPhysics, AppliedSCI(E)EI3ARTICLE62304-23082
Ultrashallow SIMS Study of Implanted Dopants in NiSi/Si(100)
No full textABSTRACTUltrashallow doping of silicon wafers with boron was done by implantation of B+ or BF2+. Nickel silicide on them was formed by annealing of thin Ni layer. As it was revealed by secondary ion mass spectrometry, after the growth of NiSi, boron remains in Si just under the silicide layer, but fluorine accumulates in the NiSi layer. This accumulation suppresses agglomeration of the silicide.</jats:p
The lava lake-induced volcanic plume at Nyiragongo Volcano (DRC): Environmental effects on crop and population
No full textEffect of carbon on Schottky barrier heights of NiSi modified by dopant segregation
No full textThe presence of carbon at the interface between NiSi and Si has been found to participate in the process of modification of effective Schottky barrier heights using the dopant segregation (DS) method. Carbon alone results in an increased ∅bn from 0.7 to above 0.9 eV. Boron diffusion in NiSi is inhibited by carbon, and no B-DS at the NiSi/Si interface occurs below 600°C. Above this temperature, B-DS at this interface is evident thus keeping φbn high. The presence of interfacial carbon leads to an increased interfacial As concentration resulting in beneficial effects in tuning ∅bp above 1.0 eV by As-DS.</p
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