1,720,969 research outputs found
Cobalt metallorganic chemical vapor deposition and formation of epitaxial CoSi2 layer on Si(100) substrate
No full textAn epitaxial CoSi2 layer was grown on Si(100) substrate by the diffusion of Co from a cobalt-carbon film without the use of an interlayer, which is usually required between the Si and cobalt layers for the formation of epitaxial CoSi2 layers. Co-C and pure Co layers were deposited by metallorganic chemical vapor deposition using the Co precursor cyclopentadienyl dicarbonyl cobalt, Co(eta(5)-C5H5)(CO)(2), and cobalt carbonyl, Co-2(CO)(8), at 350 and 200 degrees C, respectively. The CoSi2 layer was epitaxially grown on Si(100) substrate from Co-C by ex situ rapid thermal annealing at 800 degrees C in N-2 ambient. However, the polycrystalline CoSi2 layer was formed from pure Co film under the same annealing conditions. The supply of Co to the interface by diffusion in the Co-C film seems to be lower enough than in the pure Co film, resulting in an epitaxial CoSi2 layer on Si(100) substrate. (C) 1999 The Electrochemical Society. All rights reserved.The Korea Advanced Institute of Science and Technology assisted in meeting the publication costs of this article
In situ growth of an epitaxial CoSi2 layer on a Si(100) substrate by reactive chemical-vapor deposition using a cobalt metallorganic source
No full textUniform epitaxial CoSi2 layers have been grown in situ on a (100) Si substrate at temperatures above 600 degrees C by reactive chemical-vapor deposition of cyclopentadienyl dicarbonyl cobalt, Co(eta(5)-C5H5)(CO)(2). Co-rich phases such as Co2Si and CoSi were suppressed during cobalt metallorganic chemical-vapor deposition at substrate temperatures above 500 degrees C. A thin carbon layer was found on the top of the epitaxial CoSi2 layer grown on the Si substrate due to incomplete decomposition of the cobalt metallorganic source and diffusion of Co into the Si substrate. In spite of the existence of a surface carbon layer, an ion channeling minimum yield, chi(min), of 8% in Rutherford backscattering/channeling spectrometry has been achieved in the epitaxial layer, indicating a nearly perfect epitaxial order. The carbon pileup on the surface of the CoSi2 layer at the initial stage of Co deposition seems to play the role of a cobalt diffusion barrier, avoiding the formation of Co-rich phases. (C) 1999 American Institute of Physics. [S0003-6951(99)02021-5].The authors thank Dr. Dong Kyun Sohn in the R&D division of LG Semicon Co. Ltd. for useful discussions on RBS and TEM analysis
Improved morphological stability of CoSi2 layer by in situ growth on polycrystalline silicon using reactive chemical vapor deposition
No full textCoSi2 layers have been grown in situ on undoped polycrystalline silicon by reactive chemical vapor deposition of Co(eta (5)-C5H5)(CO)(2) at 650 degreesC, and their stability has been investigated in the temperature range from 800 to 1000 degreesC. The CoSi2 layers grown by the in situ method had grains with a strong (111) orientation, while no (111) orientation appeared in the CoSi2 layers grown by the conventional two-step method where CoSi formed first and transformed to CoSi (2). The stability of the CoSi (2) layers grown by the in situ process was improved by 100 degreesC over that of the CoSi2 layers grown by the conventional two-step process. The CoSi2 layers grown in situ on a large-grained polycrystalline silicon were stable up to 950 degreesC. The effect of stability improvement by the in situ growth was more pronounced when the grains of the polycrystalline silicon had a small size. The improved stability of the CoSi2 layers grown in situ may be mainly due to the formation of a uniform CoSi2 layer with the grains of (111) orientation. (C) 2001 The Electrochemical Society.The Korea Science and Engineering Foundation ~KOSEF! financially supported this work.
Korea Institute of Science and Technology assisted in meeting the publication
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Hydrogen plasma pretreatment effect on the deposition of aluminum thin films from metalorganic chemical vapor deposition using dimethylethylamine alane
No full textTo study the effect of pretreatment of substrates on the deposition behavior of Al thin films, the surfaces of TiN and SiO2 substrates were exposed to hydrogen plasma or Ar plasma before Al deposition. The Al films were deposited by the pyrolysis of dimethylethylamine alane (DMEAA). A uniform Al film was deposited by the hydrogen plasma exposure to a SiO2 substrate, while island grains were grown by the Ar plasma exposure. The pretreatments of a TiN substrate did not affect the deposition rate of the Al film. The concentration of OH radicals at the SiO2 surface was increased by the hydrogen plasma treatment. We suggest a model in which OH radicals enhance the adsorption of DMEAA on a SiO2 surface, resulting in a larger number of nucleation sites. (C) 1999 American Vacuum Society. [S0734-2101(99)04003-8]
Growth behavior and thermal stability of epitaxial CoSi2 layer from cobalt-carbon films on (100) Si substrate
No full textA uniform epitaxial CoSi2 layer was grown on (100) Si substrate by rapid thermal annealing at 800 degrees C in N-2 ambient without capping layers from an amorphous cobalt-carbon film. The amorphous cobalt-carbon film was deposited on Si substrate by the pyrolysis of cyclopentadienyl dicarbonyl cobalt, Co(eta(5)-C5H5)(CO)(2), at 350 degrees C. The discrete epitaxial CoSi2 layers with {111} and (100) faceted interfaces were formed on (100) Si substrate at the initial stage of reaction between Co and Si. Annealing at elevated temperatures lowered the roughness of the CoSi2/Si interface. The leakage current measured on the junction, fabricated with the epitaxial CoSi2 layer and annealed at 1000 degrees C for 30 s, was as low as that of the as-fabricated junction without silicide. The result indicates that epitaxial (100) CoSi2 is thermally stable at temperatures even above 1000 degrees C and has potential application to the salicide process in subhalf micron devices. (C) 1999 American Institute of Physics. [S0021-8979(99)05618-2]
Growth of in situ CoSi2 layer by metalorganic chemical vapor deposition on Si tips and its field-emission properties
No full textWe prepared Si emitters coated with a metalorganic chemical vapor deposited CoSi2 layer to improve emission properties. The CoSi2 layer was grown in situ by reactive chemical vapor deposition of cyclopentadienyl dicarbonyl cobalt at 650 degreesC. The CoSi2 layer was conformally deposited on the Si emitter tips and had a twinned structure at the epitaxial CoSi2/Si interface in the partial region. The CoSi2-coated Si emitters showed an enhanced emission due to the increase in the number of emitting sites from the Fowler-Nordheim plot. The fluctuation of emission current was reduced by the CoSi2 coating. But the long-term stability was not much improved, which may be due to the decrease of the field enhancement factor and the number of emitting sites of the CoSi2-coated Si tip. (C) 2001 American Vacuum Society
Epitaxial growth of a (100) CoSi2 layer from carbonic cobalt films deposited on (100) Si substrate using an organometallic source
No full textWe report the epitaxial growth of a (100) CoSi2 layer on Si (100) substrate by the diffusion of Co from an amorphous carbonic cobalt film. The employment of an intermediate buffer layer, usually required between Si and pure Co, was eliminated in this experiment. The amorphous carbonic cobalt film was prepared by the organometallic chemical vapor deposition of cyclopentadienyl dicarbonyl cobalt, Co(eta(5)-C5H5)(CO)(2) at 350 degrees C. The carbonic cobalt film was capped by a sputtered Ti layer to avoid oxidation of Co during annealing. A CoSi2 layer was epitaxially grown on Si (100) by ex situ rapid thermal annealing at 800 degrees C in N-2 ambient. The supply of Co by diffusion in the carbonic cobalt film seemed to be low enough to form an epitaxial CoSi2 layer. (C) 1999 American Institute of Physics. [S0003-6951(99)04207-2]
Epitaxial growth and thermal stability of CoSi2 layer on (100) Si from Co-C films without capping layer
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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
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