Structural and tribological properties of nitrogen doped amorphous carbon thin films synthesized by CFUBM sputtering method for protective coatings

Nitrogen doped amorphous carbon (a-C:N) films are a material that may successfully compete with DLC coatings, which have high hardness, high wear resistance, and a low friction coefficient. The a-C:N films were prepared on silicon substrate by a closed-field unbalanced magnetron sputtering method with a graphite target and using the Ar/N₂ mixture gases. And, we investigated the effects of various DC bias voltages from 0 to −300 V on the structural and tribological properties of the a-C:N films. This study was focused on improving physical properties of the a-C:N film by controlling process parameters like negative substrate DC bias voltage. The maximum hardness of the a-C:N film was 23 GPa, the friction coefficient was 0.08, and the critical load was 25 N on a Si wafer. Consequently, the structural and tribological properties of the a-C:N film showed a clear dependence on the energy of ions bombardment and the density of the sputtering and the reaction gases during film growth.     

Pulsed magnetron sputtering and ion-induced annealing of carbon films

Thin carbon films are deposited on a silicon substrate at room temperatures via the biased pulsed magnetron sputtering of graphite in the physical (Ar, Kr, Xe) and reactive (Ar: CH4) modes at a different sputtering power density varying from 40 to 550 W/cm². To ensure ion-assistance, negative bias of the substrate is set during film deposition by means of both DC and pulsed power sources. Some deposition parameters lead to a high hardness of the films (12.5 GPa), optical transparency, a surface resistance of RS > 10⁹ Ω/h, and developed nanomorphology of the sample surface which bears visible inclusions with a lateral size of 35 nm. Some of the films are annealed after deposition with a C⁺-ion beam with an energy of 20 keV. A correlation between the parameters of magnetron deposition and ion-beam modification and the examined characteristics of the films is found. Different R _S values in a wide range can be achieved by means of simple adjustment of the parameters and modes during magnetron sputtering and ion-beam modification.     

Mechanical properties of the plasma-enhanced magnetron sputtering Si-C-N coatings

The mechanical properties of plasma-enhanced magnetron sputtering Si-C-N hard coatings with various compositions are characterized. The effect of chemical composition on the microstructure and properties of coating is investigated. The results show that the microstructure and mechanical properties of Si-C-N coatings are very sensitive to chemical composition. The nanocrystalline/amorphous composite structure is beneficial to the coating's mechanical properties. It also reveals that Si-C-N coating with low Si and high C concentrations has the highest hardness (≥40 GPa) and the best wear property with dry friction coefficient about 0.2.     

Effect of gas flow ratio on the microstructure and mechanical properties of boron phosphide films prepared by reactive magnetron sputtering

Boron phosphide films were grown on silicon substrate by radio frequency reactive magnetron sputtering using boron target and hydrogen phosphine at different gas flow ratios (PH₃/Ar) at lower temperature. The chemical composition, microstructure and mechanical properties were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectrum, FTIR spectrum, surface profilometer and nano-indenter. The results indicate that the atomic ratio (P/B) rises from 1.06 up to 1.52 with the gas flow ratio increasing from 3/50 to 15/50. Simultaneously, the hardness and Young's modulus decrease from 25.4 GPa to 22.5 GPa, and 250.4 GPa to 238.4 GPa, respectively. Microstructure transforms from microcrystalline state to amorphous state along with the gas flow ratio increasing. Furthermore higher gas flow ratio leads to lower stress. The BP film prepared at the gas flow ratio of 3/50 can be contributed with the best properties.     

Effects of deposition parameters on the structure and mechanical properties of high-entropy alloy nitride films

High-entropy alloy (AlCrNbSiTiV)N nitride films are prepared using direct current (dc) reactive magnetron sputtering, with an equiatomic AlCrNbSiTiV alloy target. Experiments using the grey-Taguchi method are conducted to determine the effect of deposition parameters (dc power, substrate temperature, N₂/(N₂+Ar) flow rate and substrate bias) on the microstructure, mechanical and tribological properties. Orthogonal array (L₉ 3⁴), signal-to-noise ratio and analysis of variance are used to analyze the effect of the deposition parameters. The coated films are examined using scanning electron microscopy, an atomic force microscope, transmission electron microscopy (TEM), a tribometer and a nanoindenter. The TEM patterns confirm that the (AlCrNbSiTiV)N nitride films have a simple face-center-cubic structure. The experimental results show that a (AlCrNbSiTiV)N film coating significantly improves the mechanical properties. In the confirmation runs, using grey relational analysis, the improvement in friction coefficient is 32.5%, in corrosion current is 28.6%, in hardness H is 29.4%, in elastic modulus E is −18.3%, in H/E is 57.1 and in H³/E² is 225.0%. The samples with (AlCrNbSiTiV)N film coating are classified as HF1 and exhibit good adhesive strength.     

微波ECR磁控溅射制备SiNx薄膜的XPS结构研究

利用微波电子回旋共振等离子体增强非平衡磁控溅射法在不同N₂流量下制备无氢SiN_x薄膜.通过X光电子能谱、纳米硬度仪等表征技术,研究了不同N₂流量下制备的SiN_x薄膜的化学键结构、化学键含量、元素配比及各元素沿深度分布.研究结果表明,N₂流量是影响SiN_x薄膜化学键结构、元素配比、元素延深度分布等性质的主要因素.在N_{2关键词： x}')" href="#">SiN_x 磁控溅射 XPS 化学键结构     

Synthesis and characterization of superhard Ti-Si-N films obtained in an inductively coupled plasma enhanced chemical vapor deposition (ICP-CVD) with magnetic confinement

Using a novel inductively coupled plasma enhanced chemical vapor deposition (ICP-CVD) with magnetic confinement system, Ti-Si-N films were prepared on single-crystal silicon wafer substrates by sputtering Ti and Si (5 at.%:1 at.%) alloyed target in argon/nitrogen plasma. High-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), atomic force microscopy (AFM) and Nano Indenter XP tester were employed to characterize nanostructure and performances of the films. These films were essentially composed of TiN nanocrystallites embedded in an amorphous Si₃N₄ matrix with maximum hardness value of 44 GPa. Experimental results showed that the film hardness was mainly dependent on the TiN crystallite size and preferred orientation, which could be tailored by the adjustment of the N₂/Ar ratio. When the N₂/Ar ratio was 3, the film possessed the minimum TiN size of 10.5 nm and the maximum hardness of 44 GPa.     

Superhard Nb-Si-N composite films synthesized by reactive magnetron sputtering

By means of the reactive magnetron sputtering method, a series of Nb-Si-N composite films with different Si contents were deposited in an Ar, N₂ and SiH₄ mixture atmosphere. These films’ chemical composition, phase formation, microstructure and mechanical properties were characterized by the energy dispersive spectroscopy, X-ray diffraction, transmission electron microcopy, atomic force microscopy and nanoindentation. The experimental results showed that the silicon content in the Nb-Si-N composite films can be conveniently controlled by adjusting the SiH₄ partial pressure in mixed gas. The hardness and elastic modulus of the Nb-Si-N films were remarkably increased with a small amount of silicon addition and reached their maximum values of 53 and 521 GPa, respectively, at 3.4 at.% Si. Such an obvious enhancement of mechanical properties is related to the increment of crystal defects in the Nb-Si-N films. With silicon content increasing in the films further, the mechanical properties decreased gradually to somewhat a bit lower than those of the NbN film.     

反应磁控溅射法制备的氟化类金刚石薄膜的XPS结构研究

采用射频反应磁控溅射法用高纯石墨作靶、三氟甲烷(CHF₃)和氩气(Ar)作源气体制 备了氟化类金刚石（FDLC）薄膜，通过XPS光谱结合拉曼光谱、红外透射光谱和紫外 可见光光谱研究了源气体流量比等工艺条件对薄膜中键结构、sp2/sp3杂化比以及光学带隙等性能的影响.结果表明在低功率(60W)、高气压(2.0Pa)和适当的流量比(Ar/CHF₃=2∶ 1)下利用射频反应磁控溅射法可制备出氟含量高且具有较宽光学带隙和超低介电常数的FDLC薄膜. 关键词： 反应磁控溅射 氟化类金刚石薄膜 红外透射光谱 XPS光谱     

Structure,phase evolution and properties of Ta films deposited using hybrid high-power pulsed and DC magnetron co-sputtering

Crystalline phase and microstructure control are critical for obtaining desired properties of Ta films deposited by magnetron sputtering. Structure, phase evolution and properties of Ta films deposited by using hybrid high power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) under different fractions of DCMS power were investigated, where Ta ion to Ta neutral ratios of the deposition flux were changed. The results revealed that the number of Ta ions arriving on the substrate/growing film plays an important role in structure and phase evolution of Ta films. It can effectively avoid the unstable arc discharge under low pressure and show a higher deposition rate by combining HiPIMS and DCMS compared with only HiPIMS. Meanwhile, the high hardness α -Ta films can be directly deposited by hybrid co-sputtering compared to those prepared by DCMS. In the co-sputtering technology, pure α -Ta phase films with extremely fine, dense and uniform crystal grains were obtained, which showed smooth surface roughness (3.22 nm), low resistivity (38.98 μΩ · cm) and abnormal high hardness (17.64 GPa).     

Role of carbon in the formation of hard Ge1−xCx thin films by reactive magnetron sputtering

We have deposited germanium carbide (Ge_1−xC_x) films on Si(1 0 0) substrate via radio-frequency (RF) reactive magnetron sputtering in a CH₄/Ar mixture discharge, and explored the effects of carbon content (x) on the chemical bonding and hardness for the obtained films. We find that x significantly influences the chemical bonding, which leads to a pronounced change in the hardness of the film. To reveal the relationship between the chemical bonding and hardness, first-principles calculations have been carried out. It is shown that as x increases from 0 to 0.33, the fraction of sp³ C-Ge bonds in the film increases at the expense of Ge-Ge bonds, which promotes formation of a strong covalently bonded network, and thus enhances the hardness of the film. However, as x further increases from 0.33 to 0.59, the fraction of sp³ C-Ge bonds in the film gradually reduces, while that of sp³ C-H and graphite-like sp² C-C bonds increases, which damages the compact network structure, resulting in a sharp decrease in the hardness. This investigation suggests that the medium x (0.17<x<0.40) is most favorable to the preparation of hard Ge_1−xC_x films due to the formation of dominant sp³ C-Ge bonds.     

Structural and mechanical characteristics of (1 0 3) AlN thin films prepared by radio frequency magnetron sputtering

The (1 0 3)-oriented aluminum nitride (AlN) thin film is an attractive piezoelectric material for the applications in surface acoustic wave and film bulk acoustic wave resonator devices. In this work, we repot structural and mechanical characteristics of (1 0 3) AlN thin films deposited onto (1 0 0) Si substrates with radio frequency magnetron sputtering at different sputtering powers at 150, 250, and 350 W. Comparisons were made on their crystalline structures with X-ray diffraction, surface morphologies with atomic force microscopy, mechanical properties with nanoindentation, and tribological responses with nanoscratch. Results indicate that for the sputtering power of 350 W, a high-quality (1 0 3) AlN thin film, whose hardness is 18.91 ± 1.03 GPa and Young's modulus is 242.26 ± 8.92 GPa, was obtained with the most compact surface condition.     

Crystal structure and tribological properties of molybdenum disulfide films prepared by magnetron sputtering technology

Molybdenum disulfide (MoS₂) is widely used in practice due to its excellent lubricating properties. However, research on the tribological properties of magnetron sputtering for depositing MoS₂ films remains limited. Herein, the tribological properties of MoS₂ films were investigated in detail through a series of characterization and friction coefficient tests. MoS₂ films were deposited onto silicon substrates by magnetron sputtering under different radio-frequency powers (P_rf). With increased P_rf, the crystallinity of the films gradually increases, whereas the friction coefficient initially decreases and then increases. P_rf also affects the chemical composition, surface morphology, and grain size of MoS₂ films. At P_rf = 300 W, the film surface is dense and smooth, the grain distribution is uniform. Moreover, the films have superior tribological properties and low friction coefficient, which can be attributed to the weak van der Waals force among MoS₂ layers and the microscopic morphology of the films. All these results indicate that by reasonably controlling the preparation parameters, MoS₂ films with excellent tribological properties can be prepared by magnetron sputtering.     

The influence of processing gas on the mechanical properties of sputtered B-C-N-H films

This work describes the microstructure and mechanical properties of B-C-N-H films synthesized by medium frequency magnetron sputtering from a boron target in a N₂ + CH₄ + Ar gas mixture. The increase in the CH₄ flow rate increases the carbonaceous compound species, causes the increase of the C atomic concentration and promotes the formation of sp³-hybridized carbon. The change of hardness with the CH₄ flow rate had a relationship with the residual stress. The coefficient of friction was reduced approximately from 0.8 to 0.18, and wear resistance was considerably improved by increasing the flow of CH₄ gas component from 0 to 40 sccm. The change of films’ hardness was discussed and attributed primarily to the internal defects and bonding characteristics, while the superior tribological properties of the films could be assigned to the formation of sp³-hybridized carbon and the C-H bonding.     

不同射频输入功率下制备的氟化类金刚石碳膜疏水性研究

以高纯石墨作靶、氩气（Ar）和三氟甲烷（CHF₃）为源气体,用反应磁控溅射法在不同射频功率下制备了氟化类金刚石碳（F-DLC）膜,并对其疏水性进行研究.双蒸水液滴与膜表面接触角的测试结果表明,所制备薄膜表面的最大水接触角可达115°左右.通过原子力显微镜获得的薄膜表面AFM图谱、拉曼光谱以及傅里叶变换红外光谱探讨了影响薄膜的疏水性的因素.结果表明,薄膜的疏水性与薄膜的表面粗糙度和表面键结构直接相关,表面粗糙度越大,疏水性越好,但与薄膜中的F含量和sp³/sp²的比值并未呈单调增加或减小的对应关系.射频输入功率影响着薄膜的沉积速率,与薄膜表面粗糙度、薄膜中芳香环单核的比例以及薄膜表面的键结构（F的接入方式）直接相关. 关键词： 疏水性 反应磁控溅射 氟化类金刚石膜 射频功率     

非平衡磁控溅射制备类石墨碳膜及性能研究

利用中频非平衡磁控溅射技术在单晶硅基底上沉积了类石墨碳膜, 采用Raman光谱、高分辨透射电子显微镜、原子力显微镜分析了薄膜微观结构和表面形貌; 采用纳米压痕仪和CSM摩擦磨损试验机测试了碳膜力学性能和摩擦学性能. 结果表明: 利用中频非平衡磁控溅射技术沉积的碳膜是一种以sp²键合碳为主、结构非晶、硬度适中、应力较低、表面粗糙度较大、摩擦性能优异的薄膜. 脉冲占空比对薄膜微观结构和性能有显著影响, 随着脉冲占空比的增大, Raman光谱D峰和G峰的强度比I_D/I_G先减小后增大, 而硬度随脉冲占空比的增大却呈现出相反的变化趋势, 即先增大后减小; 大气氛围中的摩擦性能测试表明, 本实验制备的薄膜具有优异的抗磨性能(～10^-11 cm³/N^-1. m^-1)和承载能力(～2.5 GPa). 随脉冲占空比的增大, 薄膜摩擦系数变化甚微而磨损率却呈现先显著减小后轻微增大的变化趋势. 类石墨碳膜优异的摩擦学性能主要归因于其独特的结构、较低的内应力及良好的结构稳定性.     

Surface characteristics and nanoindentation study of Ni-Mn-Ga ferromagnetic shape memory sputtered thin films

In present paper, the off-stoichiometric Ni-Mn-Ga ferromagnetic shape memory alloy thin films are fabricated using radio frequency magnetron sputtering method. The compositions, microstructures and mechanical properties of the thin films are characterized by energy dispersive X-ray spectrum (EDAX), X-ray photoelectron spectroscopy (XPS), scanning electronic microscope (SEM), atomic force microscope (AFM) and nanoindentation test, respectively. The results show that there is a thinner layer of oxides consisting of NiO, Ga₂O₃ and an unspecified manganese oxidation (Mn_xO_y) at the surface, whereas a small amount of MnO precipitates exist in internal layers of post-annealed Ni-Mn-Ga thin films. The hardness and elastic modulus decrease with increasing film thickness. Nanoindentation tests reveal that the hardness and elastic modulus of the films can be up to 5.5 and 155 GPa, respectively. The Ni-Mn-Ga thin films have remarkably improved the ductility of Ni-Mn-Ga ferromagnetic shape memory alloys bulk materials.     

Influence of sputtering power and Ar–N2 flow on the structure and optical properties of indium nitride films prepared by magnetron sputtering

ABSTRACT

This paper discusses the deposition of indium nitride (InN) thin films on Si (100) substrates by using pulsed DC magnetron sputtering. Effects of varying sputtering power and Ar–N₂ flow ratio on the structural, morphological, and optical properties of indium nitride (InN) films were investigated. The structural characterization indicated nanocrystalline InN film with preferred orientation towards (101) plane that exhibited the optimum crystalline quality at 130?W and for 40:60 Ar–N₂ ratio. The surface morphology of InN, as observed through FESEM, contained irregularly shaped nanocrystals with size that increases with higher sputtering power and Ar:N₂ flow ratio. The optical properties of InN films were studied using ellipsometer at room temperature. The band gap of InN was decreased with the increase of sputtering power to 130?W, whereas an increase in the band gap was noticed with the increase of the Ar:N₂ flow ratio.     

Influence of nanocrystalline structure and composition on hardness of thin films based on TiO<Subscript>2</Subscript>

In this work, the influence of Tb-doping on structure, and especially hardness of nanocrystalline TiO₂ thin films, has been described. Thin films were formed by a high-energy reactive magnetron sputtering process in a pure oxygen atmosphere. Undoped TiO₂-matrix and TiO₂:Tb (2 at. % and 2.6 at. %) thin films, had rutile structure with crystallite sizes below 10 nm. The high-energy process produces nanocrystalline, homogenous films with a dense and close packed structure, that were confirmed by X-ray diffraction patterns and micrographs from a scanning electron microscope. Investigation of thin film hardness was performed with the aid of a nanoindentation technique. Results of measurements have shown that the hardness of all manufactured nanocrystalline films is above 10 GPa. In the case of undoped TiO₂ matrix, the highest hardness value was obtained (14.3 GPa), while doping with terbium results in hardness decreasing down to 12.7 GPa and 10.8 GPa for TiO₂:(2 at. % Tb) and TiO₂:(2.6 at. % Tb) thin films, respectively. Incorporation of terbium into TiO₂-matrix also allows modification of the elastic properties of the films.     

Structure and elastic recovery of Cr-C:H films deposited by a reactive magnetron sputtering technique

Cr-containing hydrogenated amorphous carbon (Cr-C:H) films were deposited on silicon substrates using a DC reactive magnetron sputtering with Cr target in an Ar and C₂H₂ gas mixture. The composition, bond structure, mechanical hardness and elastic recovery of the films were characterized using energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and nano-indentation. The film tribological behavior was also studied by a ball-on-disc tribo-tester. The results showed that the films deposited at low C₂H₂ flow rate (<10 sccm) presented a feature of composite Cr-C:H structure, which consisted of hard brittle chromium carbide phases and amorphous hydrocarbon phase, and thus led to the observed low elastic recovery and poor wear resistance of the films. However, the film deposited at high C₂H₂ flow rate (40 sccm) was found to present a typical feature of polymer-like a-C:H structure containing a large amount of sp³ C-H bonds. As a result, the film revealed a high elastic recovery, and thus exhibited an excellent wear resistance.