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12 pages, 5843 KiB

Open AccessEditor’s ChoiceArticle

Influence of the Gas Flow Rate on the Crack Formation of AlCoCrNi High-Entropy Metallic Film Fabricated Using Magnetron Sputtering

by Young-Soon Kim, Hae-Jin Park, Young-Seok Kim, Sung-Hwan Hong and Ki-Buem Kim

Coatings 2024, 14(1), 144; https://doi.org/10.3390/coatings14010144 - 21 Jan 2024

Cited by 3 | Viewed by 1966

Abstract

In the present study, the AlCoCrNi high-entropy metallic film was deposited on a Si wafer using a magnetron sputtering system. To capture the effects of the sputtering parameters on the microstructure and mechanical properties of the film, the flow rate of Ar gas [...] Read more.

In the present study, the AlCoCrNi high-entropy metallic film was deposited on a Si wafer using a magnetron sputtering system. To capture the effects of the sputtering parameters on the microstructure and mechanical properties of the film, the flow rate of Ar gas injected into the chamber (5, 7, and 8 sccm) was controlled. All films were identified as being of BCC phase with compositions of near equiatomic proportions, regardless of the gas flow rates. Nano-scale clusters were observed on the surfaces of all films, and nano-cracks were found in the film deposited at the Ar gas flow rate of 8 sccm, unlike the films deposited at the gas flow rates of 5 and 7 sccm. Detailed microstructural analysis of film deposition at an Ar gas flow rate of 8 sccm indicated that the void boundaries contribute to the formation of nano-cracks. The nano-indentation results indicated that the Ar gas flow rate 5 sccm specimen, with the smallest cluster size at the topmost surface, showed the highest hardness (12.21 ± 1.05 GPa) and Young’s modulus (188.1 ± 11 GPa) values. Full article

(This article belongs to the Special Issue Advanced High-Entropy Materials and Coatings)

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15 pages, 5283 KiB

Open AccessArticle

Tantalum Oxide Thin Films Sputter-Deposited by Oxygen Gas Pulsing

by Nicolas Martin, Jean-Marc Cote, Joseph Gavoille and Valérie Potin

Coatings 2023, 13(11), 1932; https://doi.org/10.3390/coatings13111932 - 12 Nov 2023

Cited by 3 | Viewed by 3080

Abstract

Tantalum oxide thin films are deposited by DC reactive magnetron sputtering from a tantalum metallic target and argon + oxygen. The oxygen gas is pulsed during the deposition with a constant pulsing period T = 10 s, whereas the introduction time of the [...] Read more.

Tantalum oxide thin films are deposited by DC reactive magnetron sputtering from a tantalum metallic target and argon + oxygen. The oxygen gas is pulsed during the deposition with a constant pulsing period T = 10 s, whereas the introduction time of the reactive gas, namely the t_ON injection time, is systematically changed from 0 to 100% of T. Therefore, composition of as-deposited TaO_x films is continuously changed from pure metallic tantalum to the over-stoichiometric Ta₂O₅ material. Films adopt the body-centered cubic structure (metallic Ta) for the lowest t_ON injection time values (oxygen stoichiometry x < 1.0) and become amorphous for the longest ones. It is shown that the t_ON injection time is a key parameter to deposit either homogeneous tantalum oxides, or periodic Ta/TaO_x multilayers with alternations close to 3 nm. Optical transmittance in the visible region of the film/glass substrate system and electrical conductivity vs. temperature both exhibit a gradual evolution from metallic (σ_300K = 8.17 × 10⁵ S m⁻¹ with an opaque behavior) to semiconducting (σ_300K = 1.97 × 10³ S m⁻¹ with a semi-transparent transmittance) and finally to dielectric properties (σ_300K < 10⁻⁵ S m⁻¹ for interferential films) as a function of the oxygen concentration in the films. Full article

(This article belongs to the Special Issue Advanced Strategies in Thin Film Engineering by Physical Vapor Deposition Techniques)

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14 pages, 3250 KiB

Open AccessArticle

Optical Properties of Amorphous Carbon Thin Films Fabricated Using a High-Energy-Impulse Magnetron-Sputtering Technique

by Lukasz Skowronski, Rafal Chodun, Marek Trzcinski and Krzysztof Zdunek

Materials 2023, 16(21), 7049; https://doi.org/10.3390/ma16217049 - 6 Nov 2023

Cited by 7 | Viewed by 1944

Abstract

This paper reports the results of amorphous carbon thin films fabricated by using the gas-impulse-injection magnetron-sputtering method and differing the accelerating voltage (1.0–1.4 kV). The obtained layers were investigated using Raman spectroscopy, X-ray photoelectron spectroscopy (XRD), and spectroscopic ellipsometry (SE). The analysis of [...] Read more.

This paper reports the results of amorphous carbon thin films fabricated by using the gas-impulse-injection magnetron-sputtering method and differing the accelerating voltage (1.0–1.4 kV). The obtained layers were investigated using Raman spectroscopy, X-ray photoelectron spectroscopy (XRD), and spectroscopic ellipsometry (SE). The analysis of the Raman and XPS spectra point to the significant content of sp³ hybridization in the synthesized materials (above 54–73%). The refractive index of the films is very high—above 2.45 in the infrared spectral range. The band-gap energy (determined using the inversed-logarithmic-derivative method) depends on the discharging voltage and is in the range from 1.58 eV (785 nm) to 2.45 eV (506 nm). Based on the obtained results, we have elaborated a model explaining the a-C layers’ formation process. Full article

(This article belongs to the Section Carbon Materials)

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22 pages, 6184 KiB

Open AccessArticle

The Amorphous Carbon Thin Films Synthesized by Gas Injection Magnetron Sputtering Technique in Various Gas Atmospheres

by Rafal Chodun, Lukasz Skowronski, Marek Trzcinski, Katarzyna Nowakowska-Langier, Krzysztof Kulikowski, Mieczyslaw Naparty, Michal Radziszewski and Krzysztof Zdunek

Coatings 2023, 13(5), 827; https://doi.org/10.3390/coatings13050827 - 25 Apr 2023

Cited by 5 | Viewed by 2583

Abstract

This work presents the potential for using pulsed gas injection to produce amorphous carbon films. In this experiment, the frequency of injecting small amounts of gas was used to control the pressure amplitudes, thus achieving the conditions of plasma generation from stationary, through [...] Read more.

This work presents the potential for using pulsed gas injection to produce amorphous carbon films. In this experiment, the frequency of injecting small amounts of gas was used to control the pressure amplitudes, thus achieving the conditions of plasma generation from stationary, through quasi-stationary, to pulsed oscillations of pressure. In addition, we used various gases and their mixtures, an alternative to argon. In the experiment, we studied the energy state of the plasma. The films were examined for phase and chemical composition, surface morphology, and optical and mechanical properties. We determined low-frequency pulsed gas injections to be conditions favorable for

C ({s p}^{3}) - C ({s p}^{3})

bond formation. The plasma generated by gas injections is better ionized than that generated by static pressure. Pulsed conditions favor the plasma species to retain their kinetic energy, limiting the probability of intermolecular collision events. Since helium has a relatively high ionization energy, it is a practical addition to sputtering gas because of the increasing sp³ content in the films. The electrons created by helium ionization improve the plasma’s ionization degree. Full article

(This article belongs to the Special Issue Advanced Nanostructured Coatings Deposited by Magnetron Sputtering)

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10 pages, 5098 KiB

Open AccessArticle

Effect of Nitrogen Doping on Tribological Properties of Ta₂O₅ Coatings Deposited by RF Magnetron Sputtering

by Rui Chao, Haichao Cai, Hang Li and Yujun Xue

Materials 2022, 15(23), 8291; https://doi.org/10.3390/ma15238291 - 22 Nov 2022

Cited by 1 | Viewed by 1685

Abstract

Ta₂O₅ was deposited on quartz glass and Si substrates as a protective coating. The inherent RF magnetron sputtering power of 140 W was maintained during the deposition process. During the deposition process, amounts of 5%, 10%, and 15% of N [...] Read more.

Ta₂O₅ was deposited on quartz glass and Si substrates as a protective coating. The inherent RF magnetron sputtering power of 140 W was maintained during the deposition process. During the deposition process, amounts of 5%, 10%, and 15% of N₂ were injected, and the total sputtering gas (N₂+Ar) flow was kept at 40 sccm. The microstructure and surface morphology of the coatings were characterized, and the friction and wear experiments of the coatings were carried out. The results show that the coatings’ surface is smooth and the main chemical compositions are Ta, O, and N. The maximum average roughness of the coatings was prepared by pure argon sputtering. It is proved that the introduction of N₂ reduces the surface roughness of the coatings and increases the surface hardness and elastic modulus of the coatings. Adhesive wear and brittle fracture are the two main wear forms of coatings. The wear debris is mainly composed of columnar particles and a flake structure. Full article

(This article belongs to the Topic Materials and Surface Treatment Processes Used for Engineering Applications)

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14 pages, 3269 KiB

Open AccessFeature PaperArticle

On the Control of Hot Nickel Target Magnetron Sputtering by Distribution of Power Pulses

by Rafal Chodun, Bartosz Wicher, Katarzyna Nowakowska-Langier, Roman Minikayev, Marlena Dypa-Uminska and Krzysztof Zdunek

Coatings 2022, 12(7), 1022; https://doi.org/10.3390/coatings12071022 - 19 Jul 2022

Cited by 6 | Viewed by 2833

Abstract

This paper presents the experimental results of high-temperature sputtering of nickel targets by the Gas Injection Magnetron Sputtering (GIMS) technique. The GIMS technique is a pulsed magnetron sputtering technique that involves the generation of plasma pulses by injecting small doses of gas into [...] Read more.

This paper presents the experimental results of high-temperature sputtering of nickel targets by the Gas Injection Magnetron Sputtering (GIMS) technique. The GIMS technique is a pulsed magnetron sputtering technique that involves the generation of plasma pulses by injecting small doses of gas into the zone of the magnetron target surface. Using a target with a dedicated construction to limit heat dissipation and the proper use of injection parameters and electrical power density, the temperature of the target during sputtering can be precisely controlled. This feature of the GIMS technique was used in an experiment with sputtering nickel targets of varying thicknesses and temperatures. Plasma emission spectra and current-voltage waveforms were studied to characterize the plasma process. The thickness, structure, phase composition, and crystallite size of the nickel layers produced on silicon substrates were investigated. Our experiment showed that although the most significant increase in growth kinetics was observed for high temperatures, the low sputtering temperature range may be the most interesting from a practical perspective. The excited plasma has the highest energy in the sputtering temperature range, just above the Curie temperature. Full article

(This article belongs to the Special Issue Advances in Thin Film Fabrication by Magnetron Sputtering)

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9 pages, 2999 KiB

Open AccessArticle

Preparation of a ZnO Nanostructure as the Anode Material Using RF Magnetron Sputtering System

by Seokwon Lee, Yeon-Ho Joung, Yong-Kyu Yoon and Wonseok Choi

Nanomaterials 2022, 12(2), 215; https://doi.org/10.3390/nano12020215 - 10 Jan 2022

Cited by 13 | Viewed by 2954

Abstract

In this study, a four-inch zinc oxide (ZnO) nanostructure was synthesized using radio frequency (RF) magnetron sputtering to maximize the electrochemical performance of the anode material of a lithium-ion battery. All materials were grown on cleaned p-type silicon (100) wafers with a deposited [...] Read more.

In this study, a four-inch zinc oxide (ZnO) nanostructure was synthesized using radio frequency (RF) magnetron sputtering to maximize the electrochemical performance of the anode material of a lithium-ion battery. All materials were grown on cleaned p-type silicon (100) wafers with a deposited copper layer inserted at the stage. The chamber of the RF magnetron sputtering system was injected with argon and oxygen gas for the growth of the ZnO films. A hydrogen (H₂) reduction process was performed in a plasma enhanced chemical vapor deposition (PECVD) chamber to synthesize the ZnO nanostructure (ZnO NS) through modification of the surface structure of a ZnO film. Field emission scanning electron microscopy and atomic force microscopy were performed to confirm the surface and structural properties of the synthesized ZnO NS, and cyclic voltammetry was used to examine the electrochemical characteristics of the ZnO NS. Based on the Hall measurement, the ZnO NS subjected to H₂ reduction had a higher electron mobility and lower resistivity than the ZnO film. The ZnO NS that was subjected to H₂ reduction for 5 min and 10 min had average roughness of 3.117 nm and 3.418 nm, respectively. Full article

(This article belongs to the Special Issue Transparent Conductive Nanomaterials: Science and Applications)

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13 pages, 2117 KiB

Open AccessFeature PaperArticle

Tuning the Optical Properties of WO₃ Films Exhibiting a Zigzag Columnar Microstructure

by Charalampos Sakkas, Jean-Yves Rauch, Jean-Marc Cote, Vincent Tissot, Joseph Gavoille and Nicolas Martin

Coatings 2021, 11(4), 438; https://doi.org/10.3390/coatings11040438 - 10 Apr 2021

Cited by 6 | Viewed by 2893

Abstract

Tungsten oxide WO₃ thin films are deposited by DC reactive magnetron sputtering. The Reactive Gas Pulsing Process (RGPP) associated with the GLancing Angle Deposition method (GLAD) are implemented to produce zigzag columnar structures. The oxygen injection time (t_ON time) and [...] Read more.

Tungsten oxide WO₃ thin films are deposited by DC reactive magnetron sputtering. The Reactive Gas Pulsing Process (RGPP) associated with the GLancing Angle Deposition method (GLAD) are implemented to produce zigzag columnar structures. The oxygen injection time (t_ON time) and the pulsing period are kept constant. Three tilt angles α are used: 75, 80, and 85° and the number of zigzags N is progressively changed from N = 0.5, 1, 2, 4, 8 to 16. For each film, refractive index, extinction coefficient, and absorption coefficient are calculated from optical transmission spectra of the films measured in the visible region from wavelength values only. Absorption and extinction coefficients monotonously drop as the number of zigzags increases. Refractive indices are the lowest for the most grazing tilt angle α = 85°. The highest refractive index is nevertheless obtained for a number of zigzags close to four. This optimized optical property is directly correlated to changes of the microstructure, especially a porous architecture, which is favored for high tilt angles, and tunable as a function of the number of zigzags. Full article

(This article belongs to the Special Issue Glancing Angle Deposited and Anisotropic Thin Films and Coatings)

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12 pages, 1437 KiB

Open AccessArticle

Optical Properties of Titanium in the Regime of the Limited Light Penetration

by Lukasz Skowronski

Materials 2020, 13(4), 952; https://doi.org/10.3390/ma13040952 - 20 Feb 2020

Cited by 6 | Viewed by 3030

Abstract

In this study, the titanium layers from 12 to 1470 nm thick were fabricated by using the method involving dynamically changed working gas pressure (gas injection magnetron sputtering). The influence of the deposition time on the optical and electrical properties of Ti films, [...] Read more.

In this study, the titanium layers from 12 to 1470 nm thick were fabricated by using the method involving dynamically changed working gas pressure (gas injection magnetron sputtering). The influence of the deposition time on the optical and electrical properties of Ti films, as well as on their microstructure, are considered. The samples are investigated by means of spectroscopic ellipsometry, atomic force microscopy, X-ray diffraction, and confocal optical microscopy. Additionally, for the Ti layers, the sheet resistance was determined. The produced coatings exhibit privileged direction of growth (002). The obtained results show a gradual increase in the mean relaxation time of free-carriers with the increase in the thickness of titanium film. However, the plasma energy exhibits maximum for the coating with the thickness of 93 nm. For such thickness, the lowest value of optical resistivity (about 200

μ Ω

cm) was observed. It was found that the dc- and optical resistivity exhibit similar values for titanium films with thickness up to 93 nm. For thicker Ti layers, significant differences in resistivities (dc- and optical) were noticed. The behavior of the Drude parameter (the plasma energy), calculated optical resistivity, and discrepancies between values of optical and dc-resistivities for thicker Ti coatings can be explained as a result of the limited light penetration. Full article

(This article belongs to the Special Issue Functional Titanium-Based Materials: Complexes, Composites and Coatings)

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