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Sputtering

About: Sputtering is a research topic. Over the lifetime, 63425 publications have been published within this topic receiving 936159 citations.


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TL;DR: In this article, an integrodifferential equation for the sputtering yield is developed from the general Boltzmann transport equation, and solutions of the integral equation are given that are asymptotically exact in the limit of high ion energy as compared to atomic binding energies.
Abstract: Sputtering of a target by energetic ions or recoil atoms is assumed to result from cascades of atomic collisions. The sputtering yield is calculated under the assumption of random slowing down in an infinite medium. An integrodifferential equation for the yield is developed from the general Boltzmann transport equation. Input quantities are the cross sections for ion-target and target-target collisions, and atomic binding energies. Solutions of the integral equation are given that are asymptotically exact in the limit of high ion energy as compared to atomic binding energies. Two main stages of the collision cascade have to be distinguished: first, the slowing down of the primary ion and all recoiling atoms that have comparable energies---these particles determine the spatial extent of the cascade; second, the creation and slowing down of low-energy recoils that constitute the major part of all atoms set in motion. The separation between the two stages is essentially complete in the limit of high ion energy, as far as the calculation of the sputtering yield is concerned. High-energy collisions are characterized by Thomas-Fermi-type cross sections, while a Born-Mayer-type cross section is applied in the low-energy region. Electronic stopping is included when necessary. The separation of the cascade into two distinct stages has the consequence that two characteristic depths are important for the qualitative understanding of the sputtering process. First, the scattering events that eventually lead to sputtering take place within a certain layer near the surface, the thickness of which depends on ion mass and energy and on ion-target geometry. In the elastic collision region, this thickness is a sizable fraction of the ion range. Second, the majority of sputtered particles originate from a very thin surface layer (\ensuremath{\sim}5 \AA{}), because small energies dominate. The general sputtering-yield formula is applied to specific situations that are of interest for comparison with experiment. These include backsputtering of thick targets by ion beams at perpendicular and oblique incidence and ion energies above \ensuremath{\sim}100 eV, transmission sputtering of thin foils, sputtering by recoil atoms from $\ensuremath{\alpha}$-active atoms distributed homogeneously or inhomogeneously in a thick target, sputtering of fissionable specimens by fission fragments, and sputtering of specimens that are irradiated in the core of a reactor or bombarded with a neutron beam. There is good agreement with experimental results on polycrystalline targets within the estimated accuracy of the data and the input parameters entering the theory. There is no need for adjustable parameters in the usual sense, but specific experimental setups are discussed that allow independent checks or accurate determination of some input quantities.

2,552 citations

Journal ArticleDOI
TL;DR: Two cylindrically symmetric and complementary sputtering geometries, the post and hollow cathodes, were used to deposit thick coatings of various metals (Mo, Cr, Ti, Fe, Cu, and Al-alloy) onto glass and metallic substrates at deposition rates of 1000-2000 A/min under various conditions of substrate temperature, argon pressure, and plasma bombardment as mentioned in this paper.
Abstract: Two cylindrically symmetric and complementary sputtering geometries, the post and hollow cathodes, were used to deposit thick (∼25-μ) coatings of various metals (Mo, Cr, Ti, Fe, Cu, and Al-alloy) onto glass and metallic substrates at deposition rates of 1000–2000 A/min under various conditions of substrate temperature, argon pressure, and plasma bombardment. Coating surface topographies and fracture cross sections were examined by scanning electron microscopy. Polished cross sections were examined metallographically. Crystallographic orientations were determined by x-ray diffraction. Microstructures were generally consistent with the three-zone model proposed by Movchan and Demchishin [Fiz. Metal. Metalloved. 28, 653 (1969)]. Three differences were noted: (1) at low argon pressures a broad zone 1–zone 2 transition zone consisting of densely packed fibrous grains was identified; (2) zone 2 columnar grains tended to be faceted at elevated temperatures, although facets were often replaced by smooth flat surf...

2,195 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the physical vapor deposition (PVD) of thin films is presented, focusing mainly on evaporation and sputtering processes and the physics of their growth and structure.
Abstract: Thick films will be defined here as those sufficiently thick to permit evolutionary selection processes during growth to influence their structures. High rates are defined as those sufficient to deposit thick films in a reasonable time. To avoid superficiality, this review is restricted to evaporation and sputtering, i.e. to physical vapor deposition (PVD). PVD is finding increased use for applications ranging from micro­ electronics to corrosion-barrier and wear-resistant coatings, and to the synthesis of free-standing shapes with unique mechanical properties. The emphasis here is on metallic deposits and on the physics of their growth and structure. Particular attention is given to sputtering, because recent developments ih sputtering tech­ nology make thick film deposition feasible, and because the subject has not been reviewed. Several reviews have concentrated on thick film deposition by evaporation (1, 2). Structure zone models (3-5) [particularly the model proposed by Movchan & Demchishin (3), which predicts three structural forms or zones as a function of T/Tm. where T is the substrate temperature and Tm is the coating-material melting point] have come into increased use in interpreting coating microstructures. There­ fore this review is organized from thc viewpoint of the zone models. After a brief survey of certain pertinent features of evaporation and sputtering, subsequent sections discuss each of the structural zones, metallurgical phase formation, and the mechanical properties of coatings. In this review the structure zones are defined in terms of dominant physical processes rather than structural forms. This generalization permits a broader correlation with experimental observations.

1,979 citations

Journal ArticleDOI
01 Mar 2000-Vacuum
TL;DR: Magnetron sputtering has become the process of choice for the deposition of a wide range of industrially important coatings, such as hard, wear-resistant, low friction, corrosion resistant, and decorative coatings as discussed by the authors.

1,640 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023859
20221,635
2021972
20201,346
20191,533
20181,668