Thin-film-growth characteristics by computer simulation: Nanostructural changes as a function of deposition conditions (original) (raw)
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Journal of Crystal Growth, 2007
The thin-film growth has been confirmed to be assembled by an enormous number of clusters in experiments of CVD. Sequence of clusters' depositions proceeds to form the thin-film in short time as gas fluids through surface of substrate. Such growth mechanism has been mainly investigated on the basis of experiment. Due to immense cost of the experimental equipment and low level of current measurement technology, the comprehension about authentic effect of formation condition on properties of nanomaterial is limited in qualitative manner. Three quantitative items: flatness of primary deposition, adhesion between cluster and substrate, and degree of epitaxial growth were proposed to evaluate the property of thin-film. In this simulation, three different cluster sizes of 203, 653, and 1563 atoms with different velocities (0, 10, 100, 1000, and 3000 m/s) were deposited on a Cu(0 0 1) substrate whose temperatures were set between 300 and 1000 K. Four clusters and one cluster were used in primary deposition and secondary deposition, respectively. To increase initial velocity not only enhanced the speed of epitaxial growth, adhesion between clusters and substrate, but also increased the degree of epitaxy for primary deposition and secondary deposition. Exfoliation pattern of thin-film was profoundly dependent on initial velocity through comparison between adhesion of primary and secondary deposition. Moreover, the epitaxial growth became well as the temperature of substrate was raised, and the degree of epitaxy of small cluster was larger than that of larger cluster, no matter of primary and secondary deposition. r 2007 Published by Elsevier B.V.
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We present Monte Carlo simulations of metallic thin films grown by sputter deposition from an infinite target. The Monte Carlo model includes ballistic deposition from the target, surface diffusion, and polycrystalline film growth. We study materials with low atomic mobility such as those involved in "barrier layer" films for silicon devices. We discuss the mechanism leading to columnar growth and the influence of the film orientation on structure and density. Finally, we show that polycrystalline films exhibit voids at the grain boundaries, which leads to columnar growth over a wider range of conditions than that for single crystal films.
Quantitative evaluation about property of thin-film formation
Applied Surface Science, 2006
Chemical vapor deposition (CVD) is gradually emphasized as one promising method for nanomaterial formation. Such growth mechanism has been mainly investigated on basis of experiment. Due to large cost of the equipment of experiment and low level of current measurement, the comprehension about authentic effect of formation condition on properties of nanomaterial is limited in qualitative manner. Three quantitative items: flatness of primary deposition, adhesion between cluster and substrate, and degree of epitaxial growth were proposed to evaluate the property of thin film. In this simulation, three different cluster sizes of 203, 653, 1563 atoms with different velocities (0, 10, 100, 1000, 3000 m/s) were deposited on a Cu(0 0 1) substrate whose temperatures were set between 300 and 1000 K. Within one velocity range, not only the speed of epitaxial growth and adhesion between thin film and substrate were enhanced, but also the degree of epitaxy increased and the shape of thin film became more flat with velocity increasing. Moreover, the epitaxial growth became well as the temperature of substrate was raised within a certain range, and the degree of epitaxy of small cluster was larger than larger cluster. The results indicated that the property of thin film could be controlled if the effect of situations of process was made clear. #
Theoretical study on thin-film formation by parallel molecular dynamics simulation
Synthetic Metals, 2005
Chemical vapor deposition is gradually emphasized as one promising method of nanomaterial formation. Such growth mechanism has been mainly investigated on basis of experiment. Due to large cost of experiment and low level of current measurement, the comprehension about effect of formation condition on properties of nanomaterial is limited in qualitative manner. Two quantitative items: adhesion between cluster and substrate, and degree of epitaxial growth were proposed to evaluate the property of thin film. In this simulation, three different cluster sizes of 203, 653, 1563 atoms with different velocities (0, 10, 100, 1000, 3000 m/s) were deposited on Cu (0 0 1) substrate whose temperature was set between 300 and 1000 K. Within one velocity range, not only the speed of epitaxial growth and adhesion of thin film were enhanced, but also the degree of epitaxy increased with velocity increasing. Moreover, the epitaxial growth became well as the temperature of substrate was raised within a certain range, and the degree of epitaxy of small cluster was larger than larger cluster. The results indicated that the property of thin film could be controlled if the effect of situations of process was made clear.