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The work is dedicated to the investigation of blister formation in ZrN/SiN x multilayer films irradiated with He ions (30 keV) and annealed in a vacuum at 600 °C. Multilayer films were prepared by reactive magnetron sputter-deposition on Si wafers under Ar + N 2 plasma discharges. ZrN/SiN x films were deposited by sequential sputtering from elemental Zr and Si 3 N 4 targets at substrate temperature of 300 °C, with ZrN and SiN x layer thickness varying from 2 to 10 nm. According to transmission electron microscopy (TEM), the multilayer films consist of nanocrystalline (002)-oriented ZrN and amorphous SiN x layers. Surface morphology changes of ZrN/SiN x films irradiated with He ions (30 keV) and annealed in a vacuum at 600 °C were studied by scanning electron (SEM) and atomic-force microscopy (AFM) methods. It has been found that under He ions (30 keV) irradiation ZrN/SiN x multilayer films remain resistant to blistering and flaking up to fluence of 8·10 16  cm −2 . The investigations have shown influence of the crystalline and amorphous layer thicknesses on the character and damage degree of the multilayer films surface as a result of post-radiation annealing at 600 °C. In this work potential processes (mechanisms) of blister formation and flacking in ZrN/SiN x multilayer systems are discussed. [ABSTRACT FROM AUTHOR]

The phase stability, upon vacuum annealing up to 1000 °C, of nanostructured (Ti,Zr) 1− x Si x N thin films is investigated by X-ray diffraction analysis as a function of Si content (0.13 ⩽ x ⩽ 0.25) and prior irradiation with He ions (40 kV). The quaternary TiZrSiN thin films were deposited by reactive magnetron sputtering from elemental targets at the substrate temperature of 600 °C. It was found that the increase in Si content, x , results in the transformation of structure from nanocrystalline ( x = 0.13, grain size of 11 nm) to nanocomposite state (0.19 < x ⩽ 0.25, grain size of 5 nm). The phase composition of the films changes from single-phase, cubic c-(Ti,Zr)N columns with (1 1 1) preferred orientation to dual-phase system consisting of c-(Ti,Zr)N crystallites and amorphous SiN y . Irradiation with He ions at the doses of 2 × 10 16 and 5 × 10 16 cm −2 does change the phase composition of the films. It is found that the onset temperature for phase decomposition decreases from 1000 °C to 800 °C with increasing Si content for unirradiated films. The formation of a secondary ZrN phase is observed concomitantly with increased broadening of the (2 0 0) c-(Ti,Zr)N diffraction peak. For irradiated films, the subsequent annealing at 1000 °C leads to decomposition of the c-(Ti,Zr)N solid solution into TiN- and ZrN-rich phases as well as crystallization of hexagonal Si 3 N 4 phase. [ABSTRACT FROM AUTHOR]

The influence of irradiation with He + ions on the thermal stability of TiZrN and (Ti,Zr) 0.54 Al 0.46 N nanocrystalline films was studied. The TiZrN and (Ti,Zr) 0.54 Al 0.46 N films were prepared by reactive magnetron sputtering. XRD research showed that the TiZrN and (Ti,Zr) 0.54 Al 0.46 N films were single-phase systems (based on cubic c-(Ti,Zr)N and cubic c-(Ti,Zr,Al)N solid solutions) with nanocrystalline (grain size 30 and 21 nm, respectively) structure. The irradiation with He + ions and thermal annealing up to 800 °C do not affect the structure and phase composition of the (Ti,Zr) 0.54 Al 0.46 N film. The prior irradiation of the (Ti,Zr) 0.54 Al 0.46 N film with He + ions activates spinodal decomposition of the c-(Ti,Zr,Al)N solid solution after thermal annealing at 1000 °C due to redistribution of the components of the solid solution inside the grains. [ABSTRACT FROM AUTHOR]

The effects of ion irradiation (180 keV Xe2+, doses 1×1016 cm-2 and 5×1016 cm-2) on the structure, phase composition and hardness of thin (300 nm) nanocomposite (Ti,Zr)1-xSixNy films deposited by magnetron sputtering (silicon concentration x≤0.22) were studied. It was found that the increase in Si content results in the transformation of structure from nanocrystalline (x ≤ 0.07, grain size about 18 nm) to nanocomposite (0.07 ≤ x ≤ 0.11, grain size about 8 nm) and then to amorphous (x ≥ 0.18) state. Nanocomposite films consist of two-phase: crystalline cubic (Ti,Zr)N grains (∼ 8 nm size) surrounded by a thin amorphous a -TiSiN layer. Ion irradiation with Xe ions triggers the crystallization of (Ti,Zr)N-rich grains for amorphous films (x≥0.18). It was found that irradiation leads to a decrease in nanoindentation hardness, due to the accumulation of Xe ion in the film, as well as the elemental redistribution of solid solution constituents in the area of collisions cascades. (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The work is dedicated to the study of the phase stability and surface erosion of a novel Zr-based multilayer system consisting of a combination of ceramic (ZrN) and metallic glass (Zr Cu) nanoscale layers after He irradiation (40 keV and doses up to 1.1 × 1018 cm−2). Periodic ZrN/Zr 1-x Cu x multilayers with elementary layer thicknesses of 5 nm/5 nm and 5 nm/10 nm and Cu content x = 0.45, 0.53, 0.61 and 0.74 were grown by magnetron sputter-deposition from Zr and Cu targets at the substrate temperature of 300 °C. X-ray diffraction and X-ray reflectivity analysis reveal that multilayered films consist of alternating nanocrystalline (nc) ZrN and amorphous (a) ZrCu layers with relatively sharp interfaces. The stability of the phase composition of nc-ZrN/a-Zr 1-x Cu x multilayer films to irradiation with helium ions up to fluence of 1.1 × 1018 cm−2 has been established. For x = 0.74, crystallization of the metallic glass layer was observed. The surface integrity of the multilayer films remained unaltered up to an ion fluence of 5 × 1017 cm−2. At higher ion fluence, surface erosion of the nc-ZrN/a-Zr 1-x Cu x films occurs by the flacking mechanism. In this case, an increase in the thickness of the amorphous Zr 1-x Cu x layer and in Cu content leads to improved radiation resistance as the critical fluence for delamination increases from 5 × 1017 cm−2 upto 8 × 1017 cm−2. [ABSTRACT FROM AUTHOR]

In an effort to address the understanding of the origin of growth stress in thin films deposited under very energetic conditions, the authors investigated the stress state and microstructure of Mo thin films grown by ion beam sputtering (IBS) as well as the stress relaxation processes taking place during subsequent thermal annealing or ion irradiation. Different sets of samples were grown by varying the IBS deposition parameters, namely, the energy E0 and the flux j of the primary ion beam, the target-to-sputtering gas mass ratio M1/M2 as well as film thickness. The strain-stress state was determined by x-ray diffraction using the sin2 ψ method and data analyzed using an original stress model which enabled them to correlate information at macroscopic (in terms of stress) and microscopic (in terms of defect concentration) levels. Results indicate that these refractory metallic thin films are characterized by a high compressive growth stress (-2.6 to -3.8 GPa), resulting from the creation of a large concentration (up to ∼1.4%) of point or cluster defects, due to the atomic peening mechanism. The M1/M2 mass ratio enables tuning efficiently the mean deposited energy of the condensing atoms; thus, it appears to be the more relevant deposition parameter that allows modifying both the microstructure and the stress level in a significant way. The growth stress comes out to be highly unstable. It can be easily relaxed either by postgrowth thermal annealing or ion irradiation in the hundred keV range at very low dose [<0.1 dpa (displacement per atom)]. It is shown that thermal annealing induces deleterious effects such as oxidation of the film surface, decrease of the film density, and in some cases adhesion loss at the film/substrate interface, while ion irradiation allows controlling the stress level without generating any macroscopic damage. [ABSTRACT FROM AUTHOR]

In the present work, the influence of silicon content on the surface blistering of ZrSiN nanocomposite films after He ion irradiation (energy of 30 keV and doses up to 8 × 1016 cm−2) and post-radiation annealing at the temperature of 600 °C was investigated. Using SEM, TEM and AFM methods, the influence of amorphous/crystalline boundaries on the formation of blisters in the n-ZrN/a-Si 3 N 4 nanocomposites was studied. ZrSiN nanocomposite films (~300 nm thick) were deposited at 600 °C onto (001) Si wafers by reactive unbalanced magnetron sputtering technique. Silicon concentration was varied from 7.1 to 23.1 at.%. While helium ion irradiation (at the dose of 8 × 1016 cm−2) did not change the surface morphology of the nanocomposite films, the alteration of the surface was observed after vacuum annealing. It was revealed that post-radiation annealing (600 °C) of ZrN and Si 3 N 4 mononitride films resulted in surface blistering at the dose of 5 × 1016 cm−2. Rather low blister density (0.017 μm−2) after post-radiation annealing at the dose of 5 × 1016 cm−2 was also observed for the nanocomposite film with 7.1 at.% Si content. As the irradiation dose increased up to 8 × 1016 cm−2, the surface density of blisters raised significantly (0.53 μm−2). It was found that increasing of Si concentration in the nanocomposite films was beneficial for their radiation resistance. The ZrSiN nanocomposite film with maximum Si content of 23.1 at.% was the most stable, with no sign of surface blistering being detected. • Formation of amorphous ZrSiN at high Si concentrations • The effect of Si concentration on the radiation-induced surface blistering of ZrSiN nanocomposites • Growth mechanism of He bubble in ZrSiN nanocomposites [ABSTRACT FROM AUTHOR]

The stress state of sputtered Mo thin films was studied, and a detailed analysis of elastic strains, using x-ray diffraction and the “sin2 Ψ method,” was performed. The evolution of the lattice parameter under ion irradiation showed that the usual assumption of a biaxial stress state is not adequate to determine the true stress-free lattice parameter a0 of the film. An original stress model, including a hydrostatic component linked to volume distortions induced by point defects, is required. This model, which describes a triaxial stress field, allows a reliable determination of a0. Furthermore, ion irradiation was shown to be a powerful method for stress relaxation, providing a stress-free lattice parameter solely linked to chemical effects. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

(Ti,Zr) 1 − x Al x N y thin films (300 nm) with Ti:Zr ratio of ~ 1:1 and Al content in metal sublattice up to x = 0.312 were deposited at T s = 270 °C using reactive unbalanced magnetron co-sputtering in Ar + N 2 plasma discharges. The nitrogen content, y, was understoichiometric when x ≥ 0.102, despite constancy of N 2 partial pressure used during growth. The influence of Xe ion irradiation (180 keV, 1 × 10 15 − 1 × 10 17 cm − 2 ) on the structure, phase formation and mechanical properties of the films was investigated. The increase in Al content resulted in gradual evolution of the microstructure from single-phase, nanocrystalline cubic (c) solid solution (x ≤ 0.072) to dual-phase nanocomposite (x = 0.102–0.200) and then to amorphous (x = 0.312) one. Nanocrystalline and amorphous films were stable under irradiation, while crystallization occurred in nanocomposite films for a typical ion fluence of 1 × 10 16 cm − 2 . This phase transformation is associated with the reduction of compressive stress and eventually leads to the development of a net tensile stress inside crystallites. For all films, a decrease of the nanoindentation hardness was observed after an ion fluence of 5 × 10 16 cm − 2 , likely related to the incorporation of Xe impurities, as revealed by RBS data. [ABSTRACT FROM AUTHOR]

Abstract: Titanium nitride is a technological important refractory material combining the physical properties of ceramics and metal. In addition to its wide use as protective hard coating for cutting tools or metallization layer in microelectronics, it is one of the inert matrixes proposed to surround the fuel in future gas cooled fast reactor (GFR) systems. The application of low-dose inert gas ions in materials is a powerful method for studying material properties changes due to irradiation damage. In this work, the influence of Xe-ion irradiation on the structure, electrical and mechanical properties of ternary TiN-based coating is investigated. Ti x Zr1− x N (x =0, 0.25, 0.50, 0.75, 1) thin films (∼300nm thickness) were deposited on (100) Si substrate using unbalanced reactive magnetron co-sputtering. Irradiation with Xe (q =+18) ions were carried out at fluence of 8·1014 ionscm−2 and energy of 360keV. The morphology, phase and element compositions of the as-grown and irradiated samples were studied using SEM, XRD and RBS. It is found that the simultaneous sputtering of metal targets in Ar/N2 atmosphere leads to formation of ternary solid solution nitrides with Na–Cl structure with enhanced hardness compared to binary counterpart while the nanohardness decreases for binary nitrides after ion irradiation and increase is observed for ternary nitrides. A detailed analysis of elastic strains and stresses changes after ion irradiation is also performed. [Copyright &y& Elsevier]