Effects Of Nitrogen Flow Ratio Research Articles

Effects of nitrogen flow ratio on the mechanical and anticorrosive properties of cosputtered (TiZrHfTa)Nx films

In this study, TiZrHfTa films were cosputtered through cyclical gradient composition deposition by using four single-element targets connected to direct-current power supplies. Multilayered and columnar structures formed at low and high rotation speeds of the substrate holder (RH), respectively. (TiZrHfTa)Nx thin films were then prepared through reactive cosputtering by using Ar/N2 mixed gas. A high RH value resulted in these films having homogeneous structures. Without the addition of reactive nitrogen gas, the fabricated metallic Ti0.24Zr0.23Hf0.27Ta0.26 film exhibited a valence electron concentration of 4.26, which resulted in the formation of a body-centered cubic (bcc) phase; a hardness of 4.7 GPa; and an elastic modulus of 104 GPa. (TiZrHfTa)Nx films with stoichiometric ratios (x) ranging from 0.59 to 0.97 were obtained by adjusting the reactive gas ratio fN2 (N2/(N2 + Ar)) from 0.1 to 0.7. The introduction of N into the TiZrHfTa crystallites caused the bcc phase to transform into a face-centered cubic phase and enhanced the mechanical properties of the films, with their hardness and elastic modulus increasing to 13.8–25.5 and 235–290 GPa, respectively. Nanoindentation, scratch, Rockwell-C adhesion, and potentiodynamic polarization tests indicated that among the prepared (TiZrHfTa)Nx films, the (Ti0.17Zr0.25Hf0.20Ta0.38)N0.75 film exhibited the best mechanical and anticorrosive properties. Target poisoning accompanied by defect formation affected the mechanical properties of the (TiZrHfTa)Nx films. The anticorrosive properties of the (TiZrHfTa)Nx films were dominated by the high-entropy effect through alloying with Ta and the adhesion strength between the films and substrates.

Effect of nitrogen flow ratio on the structure and optical properties of AlN film

Aluminum nitride (AlN) films with different optical properties were prepared by radio frequency (RF) reactive magnetron sputtering technique under different nitrogen (N2) flow ratios. The films' microstructure and optical properties were investigated by XRD, XPS, SEM, UV-VIS and PL. The results showed that all the prepared films had hexagonal wurtzite structure and the sample prepared at 35 % N2 flow ratio obtained higher crystal quality and larger grain size (39 nm). The selective orientation of the films changed from (100) to (002) with the N2 flow ratio, accompanied with a surface morphology changed from worm-like to mixed structure, and eventually to a very regular pebble shape with a compact arrangement. The average transmission of the films exceeded 83 % in the wavelength range of 300–800 nm. The major internal defect affecting the band gap of AlN films was nitrogen-vacancy (VN), and the growth orientation and internal defects of AlN films were controlled by the N2 flow ratio to achieve the regulation of the energy band gap in a small range (5.47–5.68 eV). This can meet the requirement of solar-blind ultraviolet (<280 nm) photoelectric detection.

Anomalous effect of nitrogen flow ratio on mechanical properties of NbMoTaW:(N,O) medium entropy alloy films

In this work, nanocrystalline NbMoTaW:(N,O) thin films were prepared by magnetron sputtering. The effect of nitrogen flow ratio [RNN2/(N2 + Ar)] ranging from 0 to 0.5 on the microstructure and mechanical properties of as-deposited films is investigated. It is found that the microstructure and the mechanical properties are both dependent on RN. The structures of NbMoTaW:O films and NbMoTaW:(N,O) films are body-centered cubic and face-centered cubic, respectively. With increasing RN, the hardness of the film reduces first and then increases, showing an anomalous effect of RN on the mechanical properties compared with previous results. The anomalous effect origins from the phase transformation, dislocation density and grain boundary hardening. The surface roughness and residual stress havelittle influence on the mechanical property.

The Optimizing Effect of Nitrogen Flow Ratio on the Homoepitaxial Growth of 4H-SiC Layers

In this study, a 4H-SiC homoepitaxial layer was grown on a 150 mm 4° off-axis substrate using a horizontal hot-wall CVD reactor. The research aimed to investigate the impact of varying the C/Si ratio and temperature while also changing the N2 flow rate and N2 flow ratio on the growth rate (thickness), doping, surface roughness, and uniformity of the large-size 4H-SiC epitaxial layer. The results indicate that the growth rate and thickness uniformity of the film increases with an increase in the C/Si ratio. Additionally, adjusting the N2 flow rate in a timely manner based on the change in the C/Si ratio is crucial to achieving the best epitaxial layer doping concentration and uniformity. The study found that, as the temperature increases, the film thickness and thickness uniformity also increase. The maximum thickness recorded was 6.2 μm, while the minimum thickness uniformity was 1.44% at 1570 °C. Additionally, the surface roughness reached its lowest point at 0.81 nm at 1570 °C. To compensate for the difference in thickness and doping concentration caused by temperature distribution and uneven airflow, the N2 flow ratio was altered. In particular, at a growth temperature of 1570 °C, a N2 flow ratio of 1.78 can improve the uniformity of doping by 4.12%.

Effects of nitrogen flow ratio on the structural, mechanical, and anticorrosive properties of co-sputtered (NbTaMoW)Nx films

In this study (NbTaMoW)Nx films were fabricated through reactive co-sputtering using four pure-element targets at various nitrogen flow ratios (RN2). It was also explored the phase structures, mechanical properties, and corrosion resistance properties of these films. The results indicated that the stoichiometric ratio x of the (NbTaMoW)Nx films increased with increasing RN2, accompanied by body-centered cubic metal phases transformation to face-centered cubic covalent nitride phases. These face-centered cubic phases were classified into phases with M2N-dominant and phases with MN-dominant structures. The results also indicated that the (NbTaMoW)Nx films prepared at RN2 values of 0.2–0.4 exhibited high hardness and Young's modulus values of 29.3–31.7 and 333–396 GPa, respectively. Using potentiodynamic polarization and electrochemical impedance spectroscopy, it was determined that the corrosion resistance of the SUS420 substrate was effectively improved with the deposition of one nitrogen-free NbTaMoW film and four nitrogen-containing (NbTaMoW)Nx films. It was also observed the highest corrosion resistance in the (Nb0.16Ta0.29Mo0.32W0.23)N0.07 film because of its dense microstructure.

Effect of Nitrogen Flow Ratio on Degradation Behaviors and Failure of Magnetron Sputter Deposited Tantalum Nitride

A series of Tantalum Nitride (TaN) films under a reactive direct current magnetron sputtering method with a controlled total gas flow rate were prepared on aluminum oxide substrates. To find the nitrogen flow rate, which produced the minimum sheet resistance, TaN films deposited under a nitrogen gas flow ratio of 2.5%, 5%, 10%, 15%, 20%, 25% were characterized in terms of their structural and electrical properties. The optimum total gas flow rate was 60 sccm, revealing the lowest deviation of sheet resistance. Next, the durability and reliability at high temperatures, after heating and cooling cycles and exposure to the induced current, were tested. When the nitrogen flow ratio reaches 2.5%, it gets the maximum for the adhesion force, roughness, and deposition rate of the TaN film, and maximum values are 75.4 N, 1.1 nm, and 3.67 nm/min, respectively, and the sheet resistance of the TaN film reaches a minimum of 20.32 Ω/sq. The degradation behaviors and failure of TaN films were investigated by measuring the sheet resistance variation. To further explain the degradation of TaN films, additional analysis of their crystallinity was conducted. The results showed that TaN-based thin film resistors have high durability and reliability, and are suitable for embedded passive resistors.

Effects of Nitrogen Flow Ratio on Structures, Bonding Characteristics, and Mechanical Properties of ZrNx Films

ZrNx (x = 0.67–1.38) films were fabricated through direct current magnetron sputtering by a varying nitrogen flow ratio [N2/(Ar + N2)] ranging from 0.4 to 1.0. The structural variation, bonding characteristics, and mechanical properties of the ZrNx films were investigated. The results indicated that the structure of the films prepared using a nitrogen flow ratio of 0.4 exhibited a crystalline cubic ZrN phase. The phase gradually changed to a mixture of crystalline ZrN and orthorhombic Zr3N4 followed by a Zr3N4 dominant phase as the N2 flow ratio increased up to &gt;0.5 and &gt;0.85, respectively. The bonding characteristics of the ZrNx films comprising Zr–N bonds of ZrN and Zr3N4 compounds were examined by X-ray photoelectron spectroscopy and were well correlated with the structural variation. With the formation of orthorhombic Zr3N4, the nanoindentation hardness and Young’s modulus levels of the ZrNx (x = 0.92–1.38) films exhibited insignificant variations ranging from 18.3 to 19.0 GPa and from 210 to 234 GPa, respectively.

Effect of Nitrogen Flow Ratio on Composition, Microstructure, and Mechanical Properties of Cr-B-O-N Films Deposited by Pulsed Direct Current Magnetron Sputtering.

Nano-crystalline CrB₂ and Cr-B-O-N films with various nitrogen flow ratios were deposited using a pulsed direct current (PDC) magnetron sputtering technique. By means of electron probe micro-analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM), and atomic force microscopy, the influences of the nitrogen flow ratio on the phase constituents and microstructures of CrB₂/Cr-B-O-N films were systematically investigated. Mechanical properties including the hardness and elastic modulus were explored by a nano-indentation tester. On increasing the nitrogen flow ratio, the N and O contents in films increased linearly and tended to become saturated, whereas the Cr and B contents decreased. With an increasing nitrogen flow ratio, the microstructure changed from a dense columnar structure to a bulky columnar structure, and then to a fine and stacked dense structure. Meanwhile, the deposition rate also changed with increasing nitrogen flow ratio, owing to the changes in structure. Crystalline phases were observed by the XRD and HRTEM analyses, consisting of several nanometer-size crystallites embedded in an amorphous matrix. The dramatically decreased hardness was attributed to the large fractional volume of the softer amorphous phase BN in films.

Effect of nitrogen flow ratio on microstructure, mechanical and tribological properties of TiWSiNx thin film deposited by magnetron co-sputtering

We investigate the deposition of TiWSiNx thin films by means of the method of reactive magnetron co-sputtering, setting the nitrogen flow ratios N2/(Ar + N2) at 4.8%, 9.1%,16.7 and 33.3%. The crystallographic structure of the films was established through X-ray diffraction (XRD), the morphology and topography were evaluated through scanning electron microscopy (SEM) and atomic force microscopy (AFM), the chemical composition was evaluated through X-ray diffraction and X-ray photoelectron spectroscopy, the mechanical properties were evaluated by nanoindentation, and the wear resistance was studied via nanowear and pin-on-disk. It was found that films deposited between 4.8% and 16.7% nitrogen flow ratio exhibited an amorphous phase. As the nitrogen was increased, the films evolved into a mixture of amorphous Si3N4 and crystalline TiWN phase. Moreover, the film morphology changed to fine columnar as the nitrogen flow ratio increased. As a general observation, the hardness, resistance to plastic deformation (H3/E2), and residual stress of the samples increased as the nitrogen flow ratio increased. The maximum hardness, resistance to plastic deformation, and residual stress were 22 ± 0.4 GPa, 213 ± 20 MPa, and 1.4 ± 0.01, respectively. The lowest nanowear volume (0.47 µm3) and wear rate (11 ± 8 10−9 mm3/N mm) were obtained for films deposited at high nitrogen flow ratios. The lowest friction coefficient (0.15) was recorded for films deposited at 16.7% nitrogen flow ratio.

Effect of nitrogen flow ratio on nano-mechanical properties of tantalum nitride thin film

In this research, nanostructured tantalum nitride (TaN) thin films were deposited on 316L stainless steel substrates by reactive magnetron sputtering. The effect of nitrogen flow ratio (N2/(Ar + N2)) on the structural, mechanical and surface properties of deposited films was studied by means of XRD, SEM, Nano-indentation and AFM. The results revealed a strong correlation between the crystal structure and properties of TaN film, where the deposited film transforms from hexagonal γ-Ta2N to hexagonal ε-TaN and cubic TaN with increasing nitrogen flow ratio from 10% to 25%. In addition, it was found that increasing the nitrogen flow ratio will result in the target poisoning and lower the deposition rate, which causes the grains growth and roughening of the surface.

Effects of Nitrogen Flow Ratio on the Properties of Radiofrequency-Sputtered InGaN Films

Indium gallium nitride (InGaN) thin films have been prepared on quartz glass substrates at various nitrogen flow ratios by radiofrequency (rf) reactive magnetron sputtering. At lower nitrogen flow ratio of 30%, the as-grown InGaN film exhibits an amorphous structure. As the nitrogen flow ratio increases from 40% to 60%, grazing-incidence x-ray diffraction (GIXRD) peaks corresponding to wurtzite InGaN are observed. At higher nitrogen flow ratios of 80% and 100%, the films exhibit highly oriented fine columnar structure and the texture of the wurtzite structure changes from (0002) to (\({10{\bar{\hbox{1}}}\hbox{3}}\)). The nitrogen flow ratio has a significant effect on the crystalline orientation and the intensity of the peak signals. A redshift of the absorption edge occurs, and the bandgap Eg tends to decrease with increasing nitrogen flow ratio. The sheet resistance Rs and the resistivity ρ of the InGaN films decrease due to the contribution of the comparatively narrow intercrystalline barriers. All the InGaN films have low mobility values, and show n-type conductivity with carrier concentration depending on the nitrogen flow ratio.

Effect of nitrogen flow ratio on structure and properties of zirconium nitride films on Si(100) prepared by ion beam sputtering

In this study, zirconium nitride thin films were deposited on Si substrates by ion beam sputtering (IBS). Influence of N2/(N2+Ar) on the structural and physical properties of the films has been investigated with respect to the atomic ratio between nitrogen and zirconium. It was found that the thickness of layers decreased by increasing the F(N2). Moreover, crystalline plane peaks such as (111), (200) and (220) with (111) preferred orientation were observed due to strain energy which associate with (111) orientation in ZrN. Also, the fluctuation in nitrogen flow ratio results in colour and electrical resistivity of films.

Preparation and annealing study of TaN x coatings on WC-Co substrates

To prevent Co diffusion from cemented carbides at high temperatures, we fabricated TaN x coatings by reactive direct current (d.c.) magnetron sputtering onto 6 wt.% cobalt cemented carbide substrates, to form diffusion barrier layers. Varying the nitrogen flow ratio, N 2/(Ar + N 2), from 0.05 to 0.4 during the sputtering process had a significant effect on coating structure and content. Deposition rate reduced as the nitrogen flow ratio increased. The effects of nitrogen flow ratio on the crystalline characteristics of the TaN x coatings were examined by X-ray diffraction. The TaN x coatings annealing conditions were 500, 600, 700, and 800 °C for 4 h in air. We evaluated the performance of the diffusion barrier using both Auger electron spectroscopy depth-profiles and X-ray diffraction techniques. We also investigated oxidation resistance of the TaN x coatings annealed in air, and under a 50 ppm O 2–N 2 atmosphere, to evaluate the fabricated layers effectiveness as a protective coating for glass molding dies.

Effect of nitrogen flow ratio on the structural and optical properties of aluminum nitride thin films

Aluminum nitride (AlN) films have been deposited on glass substrates at various nitrogen flow ratios by rf reactive magnetron sputtering. The AlN film deposited at 10% of nitrogen flow ratio shows a strongly c-axis preferred orientation with a crystalline size of 100 nm, thickness of 1100 nm, and band gap energy of 4.38 eV. The optimum crystallographic structure occurs at a nitrogen flow ratio of 100%, where a considerable crystallinity enhancement of the AlN film is observed. The band gap energies E g calculated by the Tauc model and parabolic bands are well described by a relationship, E g =10 −3 X+4.39, where X is the nitrogen flow ratio. The results suggest that the nitrogen flow ratio plays a key role in growing the high-quality AlN films.

Structural and mechanical properties of multi-element (AlCrMoTaTiZr)N x coatings by reactive magnetron sputtering

(AlCrMoTaTiZr)N x high-entropy films were deposited on silicon wafer and cemented carbide substrates from a single alloy target by reactive RF magnetron sputtering under a mixed atmosphere of Ar and N 2. The effect of nitrogen flow ratio R N on chemical composition, morphology, microstructure, and mechanical properties of the (AlCrMoTaTiZr)N x films was investigated. Nitrogen-free alloy film had an amorphous structure, while nitride films with at least 37 at.% N exhibited a simple NaCl-type FCC (face-centered cubic) structure. Mixed structures occurred in films with lower nitrogen contents. Films with the FCC structure were thermally stable without phase decomposition at 1000 °C after 10 h. The (AlCrMoTaTiZr)N film deposited at R N = 40% exhibited the highest hardness of 40.2 GPa which attains the superhard grade. The main strengthening mechanisms for this film were grain-size and solid-solution strengthening. A residual compressive stress of 1.04 GPa was small to account for the observed hardness. The nitride film was wear resistant, with a wear rate of 2.8 × 10 − 6 mm 3/N m against a loaded 100Cr6 steel ball in the sliding wear test. These high-entropy films have potential in hard coating applications.

Effects of nitrogen flow ratio on the structure and properties of reactively sputtered (AlMoNbSiTaTiVZr)Nx coatings

(AlMoNbSiTaTiVZr)Nx films are reactively sputtered from an AlMoNbSiTaTiVZr equimolar target under varied nitrogen flow ratio (RN). The concentration of nitrogen increases rapidly at lower RN and then saturates at around 50 at% when RN reaches 33% and above. At lower RN (0% and 3%), film structures are amorphous and their cross-sectional microstructures are featureless. When RN is 11%, FCC nitride nanocrystals coexist with the amorphous phase. At higher RN (33% and above), films exhibit a single NaCl-type FCC structure having fine column structures and nanograins. The texture of the FCC structures changes from (1 1 1) to (2 0 0) as RN increases from 33% to 66%. Enhanced hardness is observed upon the addition of nitrogen due to the strong bondings between N and target elements. Compared with reported high-entropy alloy (HEA)/nitride films deposited without bias, (AlMoNbSiTaTiVZr)Nx exhibits the highest hardness and modulus both in its alloy and nitride states. This not only confirms the effectiveness of the present alloy design but also demonstrates that HEA design could provide a new route to enhance the mechanical properties of alloy and nitride films.

Effect of nitrogen flow ratio on the microstructure evolution and nanoindented mechanical property of the Ta–Si–N thin films

The relations among the process, microstructure, and nanomechanical properties of cosputtered Ta–Si–N thin films have been investigated. The microstructure evolution and varied hardness and elastic modulus property of Ta–Si–N were influenced by nitrogen flow ratios [FN2% = FN2/(Far + FN2) × 100%] during cosputtering together with phase formation and the composition of films. The microstructure of Ta–Si–N formed at a low 2–10 FN2% was an amorphous-like phase with nanocrystalline grains embedded in an amorphous matrix, while polycrystalline Ta–Si–N was obtained at a high 20–30 FN2%. The cubic TaN phase or (Ta1–x,Six)N solid solution is much easier to form polycrystallites than noncubic Ta5Si3, Ta2Si, and Ta2N phases from grazing incidence x-ray diffractometry results. Amorphous-like Ta–Si–N films had much higher nanohardness, stiffness, elastic recovery percentage, and a closer boundary compared to polycrystalline films. A maximum nanohardness of 15.2 GPa was obtained at 3 FN2%. An increased hardness of polycrystalline films at 20–30 FN2% is attributed to the higher amount of the hard TaN phase.

X-ray diffraction and X-ray photoelectron spectra of Fe-Cr-N films deposited by DC reactive sputtering

The effects of nitrogen flow ratio, target area ratio of Cr, and substrate temperature on the structure of DC reactive sputtered Fe-Cr-N ternary films have been studied. X-ray diffraction measurements show that Fe-Cr-N films consist of α-Fe(Cr) and γ′-(Fe,Cr)4Nx (x < 1) phases. The crystal grain of the α-Fe(Cr) phase becomes finer and a (200) texture of the γ′-(Fe,Cr)4Nx phase becomes more marked with increasing the nitrogen flow ratio. X-ray photoelectron spectra of the films show that oxidation resistance of Fe-Cr-N films is superior to that of Fe-N films, and oxides are formed only in the film surface due to contacting with the ambient atmosphere and oxygen contamination is very small in the inner parts of these films.