Study of bactericidal efficiency of magnetron sputtered TiO2 films deposited at varying oxygen partial pressure

TiO₂ thin films have been deposited at different Ar:O₂ gas ratios (20:80,70:30,50:50,and 40:60 in sccm) by rf reactive magnetron sputtering at a constant power of 200 W. The formation of TiO₂ was confirmed by X-ray photoelectron spectroscopy (XPS). The oxygen percentage in the films was found to increase with an increase in oxygen partial pressure during deposition. The oxygen content in the film was estimated from XPS measurement. Band gap of the films was calculated from the UV-Visible transmittance spectra. Increase in oxygen content in the films showed substantial increase in optical band gap from 2.8 eV to 3.78 eV. The Ar:O₂ gas ratio was found to affect the particle size of the films determined by a transmission electron microscope (TEM). The particle size was found to be varying between 10 and 25 nm. The bactericidal efficiency of the deposited films was investigated using Escherichia coli (E. coli) cells under 1 h UV irradiation. The growth of E. coli cells was estimated through the Optical Density measurement by UV-Visible absorbance spectra. The qualitative analysis of the bactericidal efficiency of the deposited films after UV irradiation was observed through SEM. A correlation between the optical band gap, particle size and bactericidal efficiency of the TiO₂ films at different argon:oxygen gas ratio has been studied.     

Microstructure and tribological properties of the a-C:H films deposited by magnetron sputtering with CH4/Ar mixture

Hydrogenated amorphous carbon (a-C:H) films were deposited on steel and silicon wafers by unbalanced magnetron sputtering under different CH₄/Ar ratios. Microstructure and properties of the a-C:H films were investigated via Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, Atomic force microscopy (AFM) and substrate curvature method. The results revealed that CH₄/Ar ratio played an important role in the H content but acted a little function on the sp³/sp² ratio of the films. Also, the internal stress of those films was relatively low (< 1 GPa), and the deposition rate decreased firstly and then increased with the decrease of the CH₄ fraction. The film deposited under CH₄/Ar = 1/1 (55 sccm/55 sccm) with moderate sp³ C-H / sp³ C-C had the best tribological properties. The composition, microstructure and properties of the a-C:H films were strongly dependent on the deposition process and composition of reactant gases.     

Influence of substrate bias, deposition temperature and post-deposition annealing on the structure and properties of multi-principal-component (AlCrMoSiTi)N coatings

Nitride films are deposited from a single equiatomic AlCrMoSiTi target by reactive DC magnetron sputtering. The influence of the substrate bias and deposition temperature on the coating structure and properties are investigated. The bias is varied from 0 to − 200 V while maintaining a substrate temperature of 573 K. And the temperature is changed from 300 to 773 K whilst maintaining a substrate bias of − 100 V. From X-ray diffraction analysis, it is found that all the as-deposited coatings are of a single phase with NaCl-type FCC structure. This is attributed to the high mixing entropy of AlN, CrN, MoN, SiN, and TiN, and the limited diffusion kinetics during coating growth. Specific aspects of the coating, namely the grain size, lattice constant and compressive stress, are seen to be influenced more by substrate bias than deposition temperature. In fact, it is possible to classify the deposited films as large grained (~ 15 nm) with a reduced lattice constant (~ 4.15 Å) and low compressive residual stresses for lower applied substrate biases, and as small grained (~ 4 nm) with an increased lattice constant (~ 4.25 Å) and high compressive residual stresses for applied biases of − 100 V or more. A good correlation between the residual stress and lattice constant under various deposition conditions is found. For the coatings deposited at − 100 V, and at temperatures above 573 K, the hardness could attain to the range of 32 to 35 GPa.Even after annealing in vacuum at 1173 K for 5 h, there is no notable change in the as-deposited phase, grain size or lattice constant of the coatings but an increase in hardness. The thermal stability of microstructure is considered to be a result of the high mixing entropy and sluggish diffusion of these multi-component coatings. For the anneal hardening it is proposed that the overall bonding between target elements and nitrogen is enhanced by thermal energy during annealing.     

Constitution, microstructure, and battery performance of magnetron sputtered Li-Co-O thin film cathodes for lithium-ion batteries as a function of the working gas pressure

Li-Co-O thin film cathodes have been deposited onto Si and stainless steel substrates by RF magnetron sputtering from a ceramic LiCoO₂ target at various working gas pressures from 0.15 to 25 Pa. Composition, crystal structure and thin film morphology were examined and properties such as intrinsic stress, conductivity and film density were determined. As-deposited films at 0.15 Pa as well as in the range between 5 Pa and 10 Pa working gas pressure showed a nanocrystalline metastable rocksalt structure with disordered cation arrangement and were nearly stoichiometric. To induce a cation ordering the films were annealed in a furnace at temperatures between 100 and 600 °C for 3 h in argon/oxygen atmosphere (Ar:O₂ = 4.5:5) of 10 Pa. This cation ordering process was observed by XRD and Raman spectroscopy. For the films deposited at 10 Pa gas pressure an annealing temperature of 600 °C leads to the formation of the high temperature phase HT-LiCoO₂ with a layered structure. The Raman spectrum of the films deposited at 0.15 Pa and annealed at 400 °C indicates the formation of the low temperature phase LT-LiCoO₂ with a cubic spinel-related structure, which is assumed to be stabilized due to high compressive stress in the film. The electrochemical characterisation of annealed thin film cathodes revealed that the discharge capacity strongly depends on the crystal structure. Thin Li-Co-O films with a perfect layered HT-LiCoO₂ structure showed the highest discharge capacities.     

Multi-component nitride coatings derived from Ti-Al-Cr-Si-V target in RF magnetron sputter

The nitride coatings comprised of various constituents Ti, Al, Cr, Si, V were deposited on mild steel by RF magnetron sputtering process. The Ti-Al-Cr-Si-V multi-component target introduced in this study was fabricated by conventional metallurgical method with atomic ratio of each selected element at 1:1:1:1:1. Different coatings were fabricated under various working pressure by adjusting nitrogen flux from 0 to 30 sccm during sputtering. Compositions of the target and the sputtered films were measured by FE-EPMA, and both of them were near equi-molar. According to XRD patterns, amorphous structures were revealed for the metallic and nitride 1 (N = 46.2 at.%) films. The face centered cubic phases were exhibited by nitride 2 and nitride 3 with nitrogen contents around 58 at.%. Two different surface morphologies were investigated by the AFM, and they were consistent with the nanostructure observed in the XRD pattern. In addition, microhardness of the nitride coatings was measured by nanoindentation, and hardness higher than 30 GPa was exhibited in both nitride 2 and nitride 3. The microhardness test provided evidence that the multi-component nitride could be a potential candidate coating for tool steel.     

Yttria-stabilized zirconia thin films deposited by pulsed-laser deposition and magnetron sputtering

Yttria-stabilized zirconia (YSZ, ZrO₂:Y₂O₃) was deposited on (100) silicon by two physical vapor deposition techniques: pulsed laser deposition (PLD) and reactive magnetron sputtering (RMS). PLD thin films were grown on silicon substrates at 500 °C from the ablation of a 8YSZ ceramic target by a KrF excimer laser. RMS thin films were obtained by direct current magnetron sputtering of a Zr/Y metallic target in an oxygen/argon atmosphere. The deposition rate of the PLD technique using an UV excimer laser delivering pulses at a repetition rate of 40 Hz was found two orders of magnitude lower than the RMS method one. Both techniques led to the growth of crystalline films with a (111) preferential orientation. PLD films were dense and featureless whereas RMS ones exhibited well defined but compact columnar structure. Growth of a YSZ film of about 1 μm covering a rough and porous commercial anode support (NiO-YSZ cermet) was successfully carried out with both methods.     

Structure-property relations in ZrCN coatings for tribological applications

ZrCN coatings were deposited by dc reactive magnetron sputtering with N₂ flows ranging from 2 to 10 sccm in order to investigate the influence of the nitrogen incorporation on structure and properties. Information about the chemical composition was obtained by glow discharge optical emission spectroscopy and Rutherford backscattering spectroscopy. The evolution of the crystal structure studied by X-ray diffraction revealed the formation of a face-centred cubic ZrCN phase for N₂ flows greater than 4 sccm. Additionally, the presence of an amorphous phase in the coatings deposited with the highest N₂ flows could be evidenced by Raman spectroscopy and X-ray photoelectron spectroscopy. This phase can act as a lubricant resulting in a low coefficient of friction as shown in the conducted ball-on-disc tests. Nanoindentation measurements showed that coatings deposited with a 6 sccm N₂ flow had the maximum hardness which also revealed the best performance in the conducted dry cutting tests.     

Novel blue-violet photoluminescence from sputtered ZnO thin films

Although wurtzite ZnO has a simple crystal structure, the mechanism of its photoluminescence is still controversial and this topic has attracted numerous research efforts. The polycrystalline ZnO thin films studied here were deposited on Si (1 0 0) substrate by sputtering in pure Ar atmosphere, and then thermally annealed in air at various temperatures ranging from 300 °C to 1050 °C. The photoluminescence spectra of the as-synthesized ZnO thin films exhibited some interesting results: two novel and remarkable blue-violet emission peaks around 415 nm and 440 nm were discovered, while the usual strong green emission peak at 450-550 nm was absent. These two blue-violet peaks might originate from zinc interstitial and zinc vacancy point defects, which were introduced during sputtering in a non-oxygen atmosphere. Strong blue-violet emissions of ZnO are highly desirable and they have great potential in light emitting and biological fluorescence labeling applications.     

Study of Electrical,Mechanical, and Tribological Properties of CrN x Thin Films as a Function of Sputtering Conditions

The influences of chemical composition and deposition power on the electrical, mechanical, and tribological properties of sputtered chromium nitride (Cr-N) thin films that can be used for development of cryogenic temperature sensor are investigated. Cr-N thin films were deposited by DC reactive magnetron sputtering technique under various nitrogen gas flows (5-20 sccm) and deposition powers (200 and 250 W). Results of chemical composition showed that films produced with 5 and 10 sccm flow of nitrogen gas were substoichiometric, while at higher flows they were overstoichiometric. The surface morphology investigation showed that grains size and surface roughness increase with nitrogen gas flow, whereas deposition power has an inverse effect on both of these parameters. The electrical results demonstrated that the substoichiometric films had a positive temperature coefficient of resistivity, and the overstoichiometric films showed a negative temperature coefficient of resistivity. The films produced at higher deposition power of 250 W showed higher hardness and lower friction coefficient and scratch volume, while variation of nitrogen gas flow in the range of 5-20 sccm did not affect these properties, significantly.     

Growth, stress and hardness of reactively sputtered tungsten nitride thin films

Tungsten nitride (WN_x) thin films were deposited on Si(100) substrates using direct current reactive magnetron sputtering in discharging a mixture of N₂ and Ar gas. The effects of nitrogen flow rate (F_N2) and substrate bias voltage (V_b) on the composition, phase structure, and mechanical properties for the obtained films were evaluated by means of X-ray photoelectron spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy and nanoindentation. The evolution of phase structure is found closely correlated to N concentration in the films. When V_b = −40 V, with increasing F_N2, the N/W atomic ratio gradually increases in the film, accompanied by a phase transition from cubic β-W to hexagonal WN through face centered-cubic (fcc)-W₂N. At F_N2 = 15 sccm, the N/W atomic ratio gradually decreases with increasing the absolute value of V_b, resulting in a transition from fcc-W₂N to cubic β-W(N) through a mixture of fcc-W₂N + β-W(N). In addition, the increase in implanted nitrogen causes the increase in the compressive stress with increasing F_N2. In contrast, although with increasing the absolute value of V_b from 80 to 160 V the N/W atomic ratio decreases, the increase of the defects caused by increasing ion bombarding energy, dominates the increase of the compressive stress. Furthermore, the maximum hardness value for the films arrives at 38.9 GPa, which is obtained at V_b = −120 V when fcc-W₂N + β-W(N) mixed structure is formed.     

Chemical structure and mechanical properties of Si-containing a-C:H and a-C thin films and their Cr- and W-containing derivatives

Si-containing a-C:H and a-C thin films with nitrogen, oxygen and transition metal (Cr and W) additives were deposited on polished single crystalline silicon substrates at room temperature by plasma activated CVD, magnetron-sputtering PVD and also by combined PACVD-PVD techniques.In particular Si-, Si-O- and Si-N-containing a-C:H films (denoted as a-C-Si, a-C-Si-O and a-C-Si-N) were deposited respectively from tetramethylsilane (TMS), hexamethyldisiloxane and hexamethyldisilazane vapourised precursors in He carrier gas by electron cyclotron wave resonance RF plasma. Cr-containing a-C:H films, further denoted as a-C-Si-Cr, were deposited with combined PVD-PACVD by sputtering chromium and carbon targets in argon and introducing TMS vapour. Wcontaining a-C films (denoted as a-C-Si-W) were deposited by PVD with simultaneous sputtering of the constituents in Ar. Detailed characterisation of the composition and chemical state of the elements present in the films were done by X-ray photoelectron spectroscopy (XPS) and X-ray induced Auger electron spectroscopy. Mechanical properties, hardness (H), reduced modulus (E) and scratch behaviour were studied by depth-sensing nanoindentation and scratch tests.In the a-C:H films, the C/Si ratio varied between 1.5 and 3.5 showing a significant deficiency of C as compared to the composition of the precursors. The Cr and W content in the a-C-Si-Cr and a-C-Si-W films varied in a very broad 2-50 at.% range.The chemical state of carbon was primarily of sp² and partly of sp³ type C-C with XPS chemical shifts for C 1s at 284.3 eV and 285.0 eV, respectively. The Si in the films is bonded predominantly to carbon (Si 2p at 100.8 eV BE) or to nitrogen in N-containing films (Si 2p at 101.3 eV BE). In the a-C-Si-Cr films Cr-C bonding states were determined (Cr 2p_3/2 at 574.5 eV and C 1s at 282.8 eV). Si formed predominantly Si-C and also Si-Cr bonds. In the a-C-Si-W, films C-Si and C-W (W 4f_7/2 at 32.3 eV) chemical bonds could be identified.It was discovered that the modified Auger parameter for silicon, α_Si (derived from the Si 2p electron and Si KLL Auger line energy), sensitively reflects the entire chemical structure of these films, including crosslinking and densification. These spectroscopic data, supported further by the increase of the bulk plasmon loss energy of the C 1s peak, were directly connected with the mechanical properties of these films. The amorphous nature of the films was deduced from the chemical state analysis and was verified also by transmission electron microscopy (TEM) and electron diffraction (ED) studies.Hardness and elastic modulus of the a-C-Si-(O,N) films could be adjusted in a wide range of approx. 5-15 GPa and 40-140 GPa, respectively. Systematic alteration of these values with the composition (C/Si, O/Si and N/Si atomic ratio) and with the chemical structure (α_Si?) was established and their interrelations are discussed. Whilst incorporation of Cr does not alter the mechanical properties, the addition of W increases H and E up to 19 GPa and 210 GPa, respectively.     

A comparative study of CrN, ZrN, NbN and TaN layers as cobalt diffusion barriers for CVD diamond deposition on WC-Co tools

Chromium, zirconium, niobium and tantalum nitrides layers have been sputtered onto WC-12 wt.% Co substrates as diffusion barriers and buffer layers for improving performances of diamond surface coating. X-ray diffraction shows under specific reactive sputtering conditions, only MN (M = Cr, Zr, Nb, Ta) type phase exits. Their electric resistivity has been measured on samples deposited onto silica under the same conditions and related to those published.Surface and transverse scanning electron microscopy shows a dense columnar morphology.Thermo chemical computing proves the stability of those nitrides against Co, hydrogen and methane up to 1150 K (877 °C). A computed diagram of nitrogen partial pressure is given for their carburization with methane showing the highest stability for ZrN and TaN. Diamond deposition for 5 h up to 1153 K (880 °C) highlights a different behaviour for each of those materials. Auger Electron Spectroscopy (AES) profiles show a massive diffusion of cobalt through the decomposed CrN layer, a transformation of TaN and NbN into carbide without diffusion of cobalt while ZrN is outstandingly well preserved.     

直流溅射沉积CrN薄膜组织结构与摩擦性能分析研究

采用直流反应溅射在304不锈钢表面沉积CrN薄膜。利用X射线衍射仪（XRD）,扫描电子显微镜（SEM）,原子力显微镜（AFM）,显微硬度计,磨损试验机与三维轮廓仪等表征氮气流量对CrN薄膜组织结构与摩擦性能的影响。研究结果表明,随着氮气流量的增加,CrN (200)晶面呈择优取向,薄膜的沉积速率随着氮气流量的增加逐渐降低。另外,薄膜的表面粗糙度随着氮气流量的增加呈先降低后增加的趋势。随着氮气流量从15 sccm增加至30 sccm时,薄膜的显微硬度先从527.34 HV增加至1042.26 HV,当氮气流量再增加至35 sccm时,薄膜的显微硬度却降低至918 HV。磨损试验表明,当氮气流量为30 sccm 时薄膜具有最小的摩擦系数0.93和磨损率2.02×10-15m3·(N·m)-1,显示最佳的磨损性能。     

Thermal plasma chemical vapor deposition of wear-resistant, hard Si-C-N coatings

Wear-resistant, hard Si-C-N coatings were synthesized in a triple torch plasma reactor using a thermal plasma chemical vapor deposition process. In this reactor, three dc plasma torches were angled so that their jets converge to form a highly chemically reactive region at the substrate. Vaporized hexamethyldisilazane (HMDSN) was injected through a central injection probe, while nitrogen or hydrogen gases were added through the torches to the argon plasma.Various dissociation, recombination and intermediate reactions were considered to determine what major species exist in the gas phase during the deposition of Si-C-N films. Reactant flow rates were varied to evaluate the thermodynamic equilibrium compositions across a linear temperature profile above the substrate and to identify the species that lead to the production of wear-resistant, hard Si-C-N films.A series of experiments were conducted at low HMDSN flows (∼ 1 sccm) and varying hydrogen and nitrogen flows. Films were characterized by micro X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. Indentation tests were conducted on the polished film cross-sections, while wear tests were carried out on the film surfaces. At substrate temperatures below 1000 °C, amorphous Si-C-N films were deposited, while higher temperatures produced crystalline composite films of α- and β-Si₃N₄ and α- and β-SiC. Films produced with hydrogen at low HMDSN flows displayed non-columnar morphology and therefore had higher wear-resistance, indicating the benefit of low reactant-to-plasma gas flow concentrations on film growth. At low HMDSN flows, low nitrogen-to-hydrogen ratios had also shown an increase in film linear density. Small variations in mechanical properties and wear were observed between films grown under low N:H flow ratio conditions (smooth film surfaces). Wear-resistance of films with columnar structures from high N:H conditions was significantly lower, while the hardness was unobtainable. This result indicates the importance of film morphology on mechanical performance.     

Fabrication and characterization of ITO thin films on heat-resistant transparent flexible clay films

Transparent conductive indium tin oxide (ITO) thin films were deposited on transparent flexible clay films with heat resistant and high gas barrier properties by rf magnetron sputtering. The electrical, structural, and optical properties of these films were examined as a function of deposition temperature. A lowest resistivity of 4.2 × 10^− 4 Ωcm and an average transmittance more than 90% in the visible region were obtained for the ITO thin films fabricated at deposition temperatures more than 300 °C. It was found that ITO thin films with low resistivity and high transparency can be achieved on transparent flexible clay film using conventional rf magnetron sputtering at high temperature, those characteristics are comparable to those of ITO thin films deposited on a glass substrate.     

Effect of sputtering pressure and rapid thermal annealing on optical properties of Ta2O5 thin films

Ta2O5 thin films were deposited by DC reactive magnetron sputtering followed by rapid thermal annealing(RTA). Influence of sputtering pressure and annealing temperature on surface characteristics, microstructure and optical property of Ta2O5 thin films were investigated. As-deposited Ta2O5 thin films are amorphous. It takes hexagonal structure (δ-Ta2O5) after being annealed at 800 ℃. A transition from δ-Ta2O5 to orthorhombic structure (L-Ta2O5) occurs at 900-1 000 ℃. Surface roughness is decreased after annealing at low temperature. Refractive index and extinction coefficient are decreased when annealing temperature is increased.     

Composite TiN–Ni thin films deposited by reactive magnetron sputter ion-plating

Composite TiN–Ni thin films were deposited by direct-current (DC) magnetron sputter ion-plating from an alloy Ti–48 at% Ni target in a mixture of argon and nitrogen gases at a total pressure of 0.1 Pa onto glass and stainless steel substrates heated to temperatures higher than 250 °C. The films deposited at the nitrogen flow Q_N2≥6.4 sccm consisted of a mixture of δ-TiN and fcc nickel phases. The effects of negative substrate bias and substrate temperature on the crystal structure of the films were studied. The substrate bias of −200 V resulted in improved crystallization of films and a smaller difference in size between the TiN and nickel grains, as compared with films deposited onto substrates at floating potential. It was possible to vary the crystal grain size of both phases by varying the substrate temperature in the range 270–430 °C. The maximum hardness measured in the films was 10.5 GPa. It is expected that the hardness can be increased by decreasing the content of nickel.     

Low temperature growth of nanocrystalline TiO2 films with Ar/O2 low-field helicon plasma

TiO₂ thin films were deposited on silicon wafer substrates by low-field (1 < B < 5 mT) helicon plasma assisted reactive sputtering in a mixture of pure argon and oxygen. The influence of the positive ion density on the substrate and the post-annealing treatment on the films density, refractive index, chemical composition and crystalline structure was analysed by reflectometry, Rutherford backscattering spectroscopy (RBS) and X-ray diffraction (XRD). Amorphous TiO₂ was obtained for ion density on the substrate below 7 × 10¹⁶ m^− 3. Increasing the ion density over 7 × 10¹⁶ m^− 3 led to the formation of nanocrystalline (~ 15 nm) rutile phase TiO₂. The post-annealing treatment of the films in air at 300 °C induced the complete crystallisation of the amorphous films to nanocrystals of anatase (~ 40 nm) while the rutile films shows no significant change meaning that they were already fully crystallised by the plasma process. All these results show an efficient process by low-field helicon plasma sputtering process to fabricate stoichiometric TiO₂ thin films with amorphous or nanocrystalline rutile structure directly from low temperature plasma processing conditions and nanocrystalline anatase structure with a moderate annealing treatment.     

Investigation of Niobium oxynitride thin films deposited by reactive magnetron sputtering

Niobium oxynitride films were deposited using reactive magnetron sputtering of a niobium target in an Ar/O₂/N₂ atmosphere with fixed nitrogen flux in direct current (DC) and pulsed modes. For the DC sputtering mode the deposition rate was found to be twice as high as for the pulsed mode at lower oxygen to nitrogen ratios (O/N). Morphology investigation by scanning electron microscopy and atomic force microscopy showed that the coatings are getting very smooth with increasing oxygen content (average roughness R_a < 0.4 nm at oxygen contents > 40 at.%). X-ray diffraction measurements revealed that the niobium oxynitride films are X-ray amorphous for oxygen contents > 40 at.%. The electrical conductivity of the coatings was studied by the 4 point-probe method and was found to decrease with increasing oxygen content. Optical properties of Nb-O-N films were analysed by spectroscopic ellipsometry and transmission spectroscopy. The refractive index of transparent and semi-transparent films was found to be in the range of 2.3 and 2.6 (at 633 nm). The experimental results will be discussed with respect to the O/N ratios (range 1.2 < O/N < ∞) or the oxygen content (range 33.7 at.% < O < 67.3 at.%) in the films as measured by Rutherford backscattering spectroscopy and particle induced X-ray emission.     

Heat treatment induced phase separation and phase transformation of ZrNxOy thin films deposited by ion plating

Nanocrystalline ZrN_xO_y thin films were deposited on p-type Si (100) substrates using hollow cathode discharge ion-plating (HCD-IP) and the films were annealed at 700 and 900 °C in the controlled atmosphere. The purpose of this study was to investigate the phase separation, phase transformation and the accompanying change of properties of the heat-treated ZrN_xO_y films deposited by ion plating. With the increase of oxygen flow rate ranging from 0 to 10 sccm, the primary phase of the as-deposited films evolved from ZrN to nearly amorphous structure and further to monoclinic ZrO₂ (m-ZrO₂). After heat treatment at 700 and 900 °C, phase transformation occurred in the samples deposited at 8 and 10 sccm O₂, where a stoichiometric crystalline Zr₂ON₂ was found to derive from m-ZrO₂ with dissolving nitrogen (m-ZrO₂(N)). The hardness of the ZrN_xO_y thin films could be correlated to the fraction of Zr₂ON₂ + m-ZrO₂. The film hardness decreased significantly as the fraction of ZrO₂ + Zr₂ON₂ exceeded ~ 60%, which was due to phase transition by increasing oxygen flow rate or phase transformation induced by heat treatment. The phase separation of m-ZrO₂ from ZrN with dissolving oxygen (ZrN(O)) may relieve the residual stress of the ZrN_xO_y specimens deposited at 5 and 8 sccm O₂, while direct formation of m-ZrO₂ increased the stress of the film deposited at 10 sccm O₂. On the other hand, the phase transformation from m-ZrO₂(N) to Zr₂ON₂ by heat treatment at both 700 and 900 °C may effectively relieve the residual stress of the ZrN_xO_y films.