Growth and characterization of W thin films with controlled Ne and Ar contents deposited by bipolar HiPIMS

Tiron, Vasile; Bulai, Georgiana; Costin, C.; Velicu, Ioana–Laura; Dincă, P.; Iancu, Decebal; Burducea, I.

doi:10.1016/j.nme.2021.101091

Cited by 8 publications

(8 citation statements)

References 36 publications

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“…As can be seen, for short negative pulses, during the reverse pulse, the plasma potential is almost constant and reach values close to the target voltage. It should be noted that the plasma potential during the positive pulse is quasi-uniformly distributed along the target-to-substrate distance, a similar observation being recently reported elsewhere [17,32]. This means that during deposition onto grounded substrate, the plasma ions are accelerated only in the substrate sheath potential.…”

Section: Films Characterizationsupporting

confidence: 80%

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Effect of Pulsing Configuration and Magnetic Balance Degree on Mechanical Properties of CrN Coatings Deposited by Bipolar-HiPIMS onto Floating Substrate

et al. 2021

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Despite its great potential for thin films deposition and technological applications, the HiPIMS technology has its own limitations including the control of ion energy and flux towards the substrate when coping with the deposition of electrical insulating films and/or the deposition onto insulating/electrically grounded substrates. The bipolar-HiPIMS has been recently developed as a strategy to accelerate the plasma ions towards a growing film maintained at ground potential. In this work, the benefits of bipolar-HiPIMS deposition onto floating or nonconductive substrates are explored. The effect of bipolar-HIPIMS pulsing configuration, magnetic balance-unbalance degree, and substrate’s condition on plasma characteristics, microstructure evolution, and mechanical properties of CrN coatings was investigated. During the deposition with a balanced magnetron configuration, a significant ion bombardment effect was detected when short negative pulses and relative long positive pulses were used. XRD analysis and AFM observations revealed significant microstructural changes by increasing the positive pulse duration, which results in an increase in hardness from 7.3 to 16.2 GPa, during deposition on grounded substrates, and from 4.9 to 9.4 GPa during the deposition on floating substrates. The discrepancies between the hardness values of the films deposited on floating substrates and those of the films deposited on grounded substrates become smaller/larger when a type I/type II unbalanced magnetron configuration is used. Their hardness ratio was found to be 0.887, in the first case, and 0.393, in the second one. Advanced application-tailored coatings can be deposited onto floating substrates by using the bipolar-HiPIMS technology if short negative pulses, relative long positive pulses together with type I unbalanced magnetron are concomitantly used.

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Section: Films Characterizationsupporting

confidence: 80%

“…The temporal evolution and the axial distribution of the plasma and floating potential were monitored using an emissive/cold probe. More details on the emissive probe measurements can be found elsewhere [32]. Figure 1 shows the schematic diagram of the experimental set-up used in this work.…”

Section: Films Depositionmentioning

confidence: 99%

Effect of Pulsing Configuration and Magnetic Balance Degree on Mechanical Properties of CrN Coatings Deposited by Bipolar-HiPIMS onto Floating Substrate

et al. 2021

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“…In both operation modes, the space-and-time evolution of the plasma potential has been recorded using an emissive probe system working in the so-called "saturated floating-potential regime" [52]. A detailed description of plasmapotential-measurement technique was reported in one of our previous works [53]. In this work, plasma-potential measurements have been performed along the TVA discharge axis, between Wehnelt cylinder and top side of the chamber wall (35 cm above the anode), using a step size of 5 mm.…”

Section: Plasma Diagnosismentioning

confidence: 99%

Efficient Removal of Methylene Blue and Ciprofloxacin from Aqueous Solution Using Flower-like, Nanostructured ZnO Coating under UV Irradiation

et al. 2022

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Flower-like ZnO architectures assembled with many nanorods were successfully synthesized through Thermionic Vacuum Arc, operated both in direct current (DC-TVA) and a pulsed mode (PTVA), and coupled with annealing in an oxygen atmosphere. The prepared coatings were analysed by scanning-electron microscopy with energy-dispersive X-ray-spectroscopy (SEM-EDX), X-ray-diffraction (XRD), and photoluminescence (PL) measurements. By simply modifying the TVA operation mode, the morphology and uniformity of ZnO nanorods can be tuned. The photocatalytic performance of synthesized nanostructured ZnO coatings was measured by the degradation of methylene-blue (MB) dye and ciprofloxacin (Cipro) antibiotic. The ZnO (PTVA) showed enhancing results regarding the photodegradation of target contaminants. About 96% of MB molecules were removed within 60 min of UV irradiation, with a rate constant of 0.058 min−1, which is almost nine times higher than the value of ZnO (DC-TVA). As well, ZnO (PTVA) presented superior photocatalytic activity towards the decomposition of Cipro, after 240 min of irradiation, yielding 96% degradation efficiency. Moreover, the agar-well diffusion assay performance against both Gram-positive and Gram-negative bacteria confirms the degradation of antibiotic molecules by the UV/ZnO (PTVA) approach, without the formation of secondary hazardous products during the photocatalysis process. Repeated cyclic usage of coatings revealed excellent reusability and operational stability.

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“…In Table 1, it can be seen for W 66 that Be plasma parameters (I, V) are significantly lower, which in turn leads to a reduced plasma density, a lower ionization yield and consequently to a reduction of the ion flux impinging on the just forming layers. On the other hand, the W50 sample has the highest power applied to both Be and W cathodes, leading to an enhanced ion bombardment during deposition and consequently to an increased ad-atom mobility which improves the crystalline structure [42]. The analysis of the diffraction peak profiles was performed in order to assess the crystalline size from the peak full width at half maximum.…”

Section: Crystalline Structurementioning

confidence: 99%

Deuterium Retention in Mixed Layers with Application in Fusion Technology

et al. 2022

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Formation of Be-W mixed layers in thermonuclear fusion reactors can potentially alter the retention of hydrogen isotopes and affect the retention and release properties of these isotopes. This paper reports on the retention and release characteristics of D from reference Be, W layers as well as three Be-W mixed layers with well-defined atomic concentrations (2:1, 1:1, 1:2). The layers resulted from the sputtering of Be and W materials in Ar:D (1:1) mixture at 2 Pa using DC magnetron sputtering. The mixed layers’ deposition parameters were varied to adjust accordingly the deposition rate for each material in order to obtain the desired concentrations. Scanning electron microscope images showed that morphology is independent of composition for samples deposited on silicon substrates. In contrast, layers deposited on tungsten revealed a textured surface and morphological changes with W concentration variation. X-ray diffraction patterns of mixed layers evidenced the presence of a polycrystalline tungsten phase. Additionally, the degree of crystallinity is highly influenced by the plasma parameters and enhanced amorphization is evidenced by a decrease of crystalline size by a factor of 10 for mixed layers compared to the W reference layer. The release behavior of D from the layers is affected by the trapping contribution of both Be and W. Compared with implanted layers, presented in literature studies, the co-deposited layers show a high D occupancy of low energy trapping states, the majority of the D retained in the samples being released at temperatures below 623 K. High energy trapping becomes more pronounced for layers with a high Be concentration. The oxygen contamination observed for Be layers points to a mitigation of D retention in low energy trapping states and shifts the desorption chart towards a higher temperature due to enhanced retention in BeO associated traps. The D retention presents a linear decrease of W concentration in the sample.

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Growth and characterization of W thin films with controlled Ne and Ar contents deposited by bipolar HiPIMS

Cited by 8 publications

References 36 publications

Effect of Pulsing Configuration and Magnetic Balance Degree on Mechanical Properties of CrN Coatings Deposited by Bipolar-HiPIMS onto Floating Substrate

Effect of Pulsing Configuration and Magnetic Balance Degree on Mechanical Properties of CrN Coatings Deposited by Bipolar-HiPIMS onto Floating Substrate

Efficient Removal of Methylene Blue and Ciprofloxacin from Aqueous Solution Using Flower-like, Nanostructured ZnO Coating under UV Irradiation

Deuterium Retention in Mixed Layers with Application in Fusion Technology

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