Effect of substrate bias and temperature on magnetron sputtered CrSiN films

The combine influence of substrate temperature and bias on microstructure and mechanical properties of CrSiN film was examined. The silicon content and phase constitutions of the films are independent on substrate temperature and bias. The crystal preferred orientation is controlled by substrate bias but unrelated to substrate temperature. The influence of bias (0 V to −300 V) on hardness is more obvious than that of the substrate temperature (100-500 °C).     

Crystallizaion and surface morphology of poly(vinylidene fluoride)/poly(methylmethacrylate) films by solution casting on different substrates

The dependence of surface structure of the poly(vinylidene fluoride) (PVDF)/poly(methylmethacrylate) (PMMA) films by solution casting on properties of seven substrates was investigated by wide angle X-ray diffraction (WAXD), Fourier transform infrared (FTIR), scanning electron microscope (SEM) and differential scanning calorimetry (DSC). It was revealed that the polyblend films obtained by casting onto each substrate contained exclusively β phase PVDF. Higher crystallinity of the film was obtained by casting onto ceramic, polytetrafluoroethylene (PTFE), copper (Cu), stainless steel and glass substrates than that by casting onto aluminium (Al) and polypropylene (PP) substrates, depending on the degree of close lattice matching. The surface crystalline structure of PVDF was strongly affected by the wettability of substrate. The largest size of PVDF spherulitic crystal structure with about 6 μm presented in the casting film grown at the air/solution interface on glass substrate, while the smallest spherulite size with about 3 μm was generated by casting onto PTFE, stainless steel and PP substrates. It implied that the higher surface tension the substrate had, the larger PVDF spherulite grew at the air/solution interface.     

Crystallization and surface morphology of Au/SiO2 thin films following furnace and flame annealing

A crystallization and surface evolution study of Au thin film on SiO₂ substrates following annealing at different temperatures above the eutectic point of the Au/Si system are reported. Samples were prepared by conventional evaporation of gold in a high vacuum (10⁻⁷ mbar) environment on substrates at room temperature. Thermal treatments were performed by both furnace and flame annealing techniques. Au thin films can be crystallized on SiO₂ substrates by both furnace and flame annealing. Annealing arranges the Au crystallites in the (1 1 1) plane direction and changes the morphology of the surface. Both, slow and rapid annealing result in a good background in the XRD spectra and hence clean and complete crystallization which depends more on the temperature than on the time of annealing. The epitaxial temperature for the Au/SiO₂ system decreases in the range of 350-400 °C. Furnace and flame annealing also form crystallized gold islands over the Au/SiO₂ surface. Relaxation at high temperatures of the strained Au layer, obtained after deposition, should be responsible for the initial stages of clusters formation. Gold nucleation sites may be formed at disordered points on the surface and they become islands when the temperature and time of annealing are increased. The growth rate of crystallites is highest around 360 °C. Above this temperature, the layer melts and gold diffuses from the substrate to the nucleation sites to increase the distance between islands and modify their shapes. Well above the eutectic temperature, the relaxed islands have hexagonally shaped borders. The mean crystallite diameters grow up to a maximum mean size of around 90 nm. The free activation energy for grain boundary migration above 360 °C is 0.2 eV. Therefore the type of the silicon substrate changes the mechanism of diffusion and growth of crystallites during annealing of the Au/Si system. Epitaxial Au(1 1 1) layers without formation of islands can be prepared by furnace annealing in the range of 300-310 °C and by flame annealing of a few seconds and up to 0.5 min.     

Influence of Si substrate preparation on surface chemistry and morphology of L-CVD SnO2 thin films studied by XPS and AFM

Results of experimental studies of the influence of substrate preparation on the surface chemistry and surface morphology of the laser-assisted chemical vapour deposition (L-CVD) SnO₂ thin films are presented in this paper. The native Si(1 0 0) substrate cleaned by UHV thermal annealing (TA) as well as thermally oxidized Si(1 0 0) substrate cleaned by ion bombardment (IBA) have been used as the substrates. X-ray photoemission spectroscopy (XPS) has been used for the control of surface chemistry of the substrates as well as of deposited films. Atomic force microscopy (AFM) has been used to control the surface morphology of the L-CVD SnO₂ thin films deposited on differently prepared substrates. Our XPS shows that the L-CVD SnO₂ thin films deposited on thermally oxidized Si(1 0 0) substrate after cleaning with ion bombardment exhibit the same stoichiometry, i.e. ratio [O]/[Sn] = 1.30 as that of the layers deposited on Si(1 0 0) substrate previously cleaned by UHV prolonged heating. AFM shows that L-CVD SnO₂ thin films deposited on thermally oxidized Si(1 0 0) substrate after cleaning with ion bombardment exhibit evidently increasing rough surface topography with respect to roughness, grain size range and maximum grain height as the L-CVD SnO₂ thin films deposited on atomically clean Si substrate at the same surface chemistry (nonstoichiometry) reflect the higher substrate roughness after cleaning with ion bombardment.     

负偏压对磁控溅射Ti膜沉积速率和表面形貌的影响

 采用直流磁控溅射加负偏压的方法制备了Ti膜,研究了不同偏压条件对Ti膜沉积速率、密度、生长方式及表面形貌的影响。随着偏压逐渐增大,Ti膜沉积速率分三个阶段变化:0~ -40 V之间沉积速率基本不变; -40~ -80 V之间沉积速率迅速降低;超过-80 V后沉积速率随偏压的下降速度又放缓。Ti膜密度随偏压增加而增大,负偏压为-119.1 V时开始饱和并趋于块体Ti材密度。加负偏压能够抑制Ti膜的柱状生长方式;偏压可以改善Ti膜的表面形貌,对于40 W和100 W的溅射功率,负偏压分别在-100 V和-80 V左右时制备出表面光洁性能较佳的Ti膜。     

Effect of annealing temperature on the decomposition of reactively sputtered Ag2Cu2O3 films

Ag₂Cu₂O₃ films were deposited on glass substrates by reactive sputtering of a composite silver-copper target. The deposited films were annealed in air at 100, 200 and 300 °C. The structure of the films was studied using X-ray diffraction (XRD), their surface morphology was characterised using scanning electron microscopy (SEM) and their electrical resistivity at room temperature was measured using the four point probe method. The 100 °C annealing did not modify either the film structure or the film morphology. On the other hand, Ag₂Cu₂O₃ films were partially decomposed into Ag and CuO after a 200 °C annealing. The decomposition was complete for a 300 °C annealing. The evolution of the film surface morphology as a function of the annealing temperature was discussed in connection to the evolution of the molar volume of the phases constituting the films.     

Photo-irradiation effects on the surface morphology of poly(p-phenylene vinylene) films

In this work, we have studied the surface morphology of photo-irradiated poly(p-phenylene vinylene) (PPV) thin films by using atomic force microscopy (AFM). We have analyzed the first-order statistical parameters, the height distribution and the distance between selected peaks. The second-order statistical analysis was introduced calculating the auto-covariance function to determine the correlation length between heights. We have observed that the photo-irradiation process produces a surface topology more homogeneous and isotropic such as a normal surface. In addition, the polymer surface irradiation can be used as a new methodology to obtain materials optically modified.     

Effect of nitrogen content on phase configuration, nanostructure and mechanical behaviors in magnetron sputtered SiCxNy thin films

SiC_xN_y thin films with different nitrogen contents were deposited by way of incorporation of different amounts of nitrogen into SiC_0.70 using unbalanced reactive dc magnetron sputtering method. Their phase configurations, nanostructures and mechanical behaviors were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM) and microindentation methods. The result indicated SiC_0.70 and all SiC_xN_y thin films exhibited amorphous irrespective of the nitrogen content. The phase configuration and mechanical behaviors of SiC_xN_y thin films strongly depended on nitrogen content. SiC_0.70 exhibited a mixture consisting of SiC, Si and a small amount of C. Incorporated nitrogen, on one hand linked to Si, forming SiN_x, on the other hand produced CN_x and C at the expense of SiC. As a result, an amorphous mixture consisting of SiC, SiN_x, C and CN_x were produced. Such effects were enhanced with increase of nitrogen content. A low hardness of about 16.5 GPa was obtained at nitrogen-free SiC_0.70. Incorporation of nitrogen or increase of nitrogen content increased the film hardness. A microhardness maximum of ∼29 GPa was obtained at a nitrogen content of 15.7 at.%. This value was decreased with further increase of N content, and finally a hardness value of ∼22 GPa was obtained at a N content of ∼25 at.%. The residual compressive stress was consistent with the hardness in the nitrogen content range of 8.6-25.3 at.%.     

氮气流量对磁控溅射InN薄膜特性的影响

采用射频磁控溅射法在蓝宝石衬底上制备了InN薄膜. 研究了N2流量对InN薄膜的晶体结构、表面形貌、光学和电学特性的影响. X射线衍射(XRD)测试结果显示,InN呈六方纤锌矿结构,具有明显(002)择优取向;SEM与AFM图像显示InN薄膜均匀致密,低N2流量下随流量增加,表面逐渐趋于光滑平整,过高的N2流量使薄膜生长方式发生改变;通过检测薄膜吸收特性,利用线性外推法计算禁带宽度为1.81~1.96 eV;电学测试结果表明,制备的薄膜样品均呈现n型导电特性,且迁移率较低,最大为12.2 cm2/v∙s;载流子浓度较高,保持在1021 cm-3数量级;电阻率较小,范围是0.202~0.33 mΩ∙cm.     

Effects of hydrogen on photoluminescence properties of a-SiNx:H films prepared by VHF-PECVD

Luminescent hydrogenated amorphous silicon nitride films were prepared with different hydrogen flow rate in very high frequency plasma enhanced chemical vapor deposition system. Very bright orange-red light emissions can be clearly observed with the naked eye in a bright room for the films grown at the hydrogen flow rate of 30 sccm. The photoluminescence intensity of the film grown at the hydrogen flow rate of 30 sccm is found to be four times higher than that of the film without hydrogen dilution. However, with further increasing the hydrogen flow rate from 30 to 90 sccm, the photoluminescence intensity of the film rapidly decreases. Fourier-transform infrared absorption spectra indicate that the introduction of hydrogen concentration bonded to silicon and nitrogen is of a key role to enhance the photoluminescence intensity of the films. Based on the measurements of structural and bonding configurations, the improved photoluminescence intensity is attributed to the well hydrogen passivation of nonradiative defect states related to N and Si at proper hydrogen flow rate.     

Surface acoustic wave device properties of (B, Al)N films on 128° Y-X LiNbO3 substrate

A c-axis orientated aluminium nitride (AlN) film on a 128° Y-X lithium niobate (LiNbO₃) surface acoustic wave (SAW) device which exhibit a large electromechanical coupling coefficient (k²) and a high SAW velocity property, is needed for future communication applications. In this study, a c-axis orientated (B, Al)N film (with 2.6 at.% boron) was deposited on a 128° Y-X LiNbO₃ substrate by a co-sputtering system to further boost SAW device properties. The XRD and TEM results show that the (B, Al)N films show highly aligned columns with the c-axis perpendicular to the substrate. The hardness and Young's modulus of (B, Al)N film on 128° Y-X LiNbO₃ substrates are at least 17% and 7% larger than AlN films, respectively. From the SAW device measurement, the operation frequency characteristic of (B, Al)N film on 128° Y-X LiNbO₃ is higher than pure AlN on it. The SAW velocity also increases as (B, Al)N film thickness increases (at fixed IDT wavelength). Furthermore, the k² of (B, Al)N on the IDT/128° Y-X LiNbO₃ SAW device shows a higher value than AlN on it.     

The dispersion properties of surface acoustic wave devices on AlN/LiNbO3 film/substrate structure

Highly c-axis oriented aluminum nitride (AlN) films were deposited on z-cut LiNbO₃ substrates by reactive rf magnetron sputtering. The crystalline properties investigated by X-ray diffraction (XRD) revealed that AlN film with (0 0 2) preferred orientation was improved by an increase of the deposition time within the experimental range. However, the surface morphology of AlN film measured by scanning probe microscopy (SPM) showed that the roughness was getting worse with increase of deposition time. Surface acoustic wave (SAW) properties, measured by a network analyzer in the structure consisting of highly c-axis AlN films on z-cut LiNbO₃ substrates, were investigated. The phase velocity (V_P) was significantly increased by the increase of h/λ, where h is the thickness of AlN film and λ is the wavelength. However, the insertion loss (IL) of SAW filters was also increased by the increase of h/λ. Experimental results on the temperature characteristics of SAW devices are also presented.     

Influence of N2:(N2 + Ar) flow ratio and substrate temperature on the properties of zirconium nitride films prepared by reactive dc magnetron sputtering

Preferred crystal orientation and low electrical resistivity are required for ZrN_x films applied in electronic devices. In this paper, effects of N₂:(N₂+Ar) flow ratio (F(N₂)) and substrate temperature on the properties of the films deposited on glass substrate by reactive dc sputtering are investigated. In a wide range of F(N₂) (4–24%), the films show fcc NaCl structure. While for F(N₂) in the ranges of 5–12, 12–24 and >24%, the films show (1 1 1)/(2 0 0), (1 1 1) only and amorphous structures, respectively. The electrical resistivity increases with F(N₂) from 5 to 24%, and can be controlled to some extent by changing the substrate temperature.     

高温退火对蓝宝石基片的表面形貌和对CeO2缓冲层以及Tl-2212超导薄膜生长的影响

研究了蓝宝石(1102)基片在不同温度和时间下退火时表面形貌和表面相结构的变化,以及它对CeO₂缓冲层和Tl-2212超导薄膜生长的影响.原子力显微镜(AFM)研究表明,在流动氧环境中1000℃温度下退火,蓝宝石(1102)的表面首先局部区域形成台阶结构,然后表面形成叠层台阶结构,随着退火时间的延长,表面发生了台阶合并现象,表面形貌最终演化为稳定的具有光滑平台的宽台阶结构.XRD测试表明,通过高温热处理可以大幅度提高蓝宝石基片表面结构的完整性.在1000℃温度下热处理20 h的蓝宝石 关键词： Tl-2212超导薄膜 蓝宝石 缓冲层     

Effect of substrate morphology on the roughness evolution of ultra thin DLC films

The effect of substrate roughness on growth of ultra thin diamond-like carbon (DLC) films has been studied. The ultra thin DLC films have been deposited on silicon substrates with initial surface roughness of 0.15, 0.46 and 1.08 nm using a filted cathodic vacuum arc (FCVA) system. The films were characterized by Raman spectroscope, transmission electron microscope (TEM) and atomic force microscopy (AFM) to investigate the evolution of the surface roughness as a function of the film thickness. The experimental results show that the evolution of the surface morphology in an atomic scale depends on the initial surface morphology of the silicon substrate. For smooth silicon substrate (initial surface roughness of 0.15 nm), the surface roughness decreased with DLC thickness. However, for silicon substrate with initial surface roughness of 0.46 and 1.08 nm, the film surface roughness decreased first and then increased to a maximum and subsequently decreased again. The preferred growth of the valley and the island growth of DLC were employed to interpret the influence of substrate morphology on the evolution of DLC film roughness.     

Surface morphological changes and magnetic properties of Sc-substituted Y3Fe5O12 epitaxial films deposited on the GGG substrate

Sc-doped YIG films were grown on (1 1 1) oriented GGG crystalline substrate with disorientation angle within the range 0-25′. Sc³⁺ ion substitution was varied within the range 0.25-0.3 per formula unit. The films demonstrate different types of surface morphology versus film growth rate and substrate disorientation. Conditions for existence of these types of the surface morphology were defined. The field dependence of magnetic susceptibility at magnetization reversal in film plane and Faraday rotation at wavelength 633 nm for a magnetic field applied in perpendicular direction were measured to characterize the films grown. Films with “mirror-like” surface demonstrate a planar magnetization at room temperature.     

高温退火对蓝宝石基片的表面形貌和对CeO2缓冲层以及Tl-2212超导薄膜生长的影响

研究了蓝宝石(1102)基片在不同温度和时间下退火时表面形貌和表面相结构的变化，以及它对CeO₂缓冲层和Tl-2212超导薄膜生长的影响.原子力显微镜(AFM)研究表明，在流动氧环境中1000℃温度下退火，蓝宝石(1102)的表面首先局部区域形成台阶结构，然后表面形成叠层台阶结构，随着退火时间的延长，表面发生了台阶合并现象，表面形貌最终演化为稳定的具有光滑平台的宽台阶结构.XRD测试表明，通过高温热处理可以大幅度提高蓝宝石基片表面结构的完整性.在1000℃温度下热处理20 h的蓝宝石     

Effect of substrate temperature on the morphology, structural and optical properties of Zn1−xCoxO thin films

Zn_1−xCo_xO thin films with c-axis preferred orientation were deposited on sapphire (0 0 0 1) by pulsed laser deposition (PLD) technique at different substrate temperatures in an oxygen-deficient ambient. The effect of substrate temperature on the microstructure, morphology and the optical properties of the Zn_1−xCo_xO thin films was studied by means of X-ray diffraction (XRD), atomic force microscopy (AFM), UV-visible-NIR spectrophotometer, fluorescence spectrophotometer. The results showed that the crystallization of the films was promoted as substrate temperature rose. The structure of the samples was not distorted by the Co incorporating into ZnO lattice. The surface roughness of all samples decreased as substrate temperature increased. The Co concentration in the film was higher than in the target. Emission peak near band edge emission of ZnO from the PL spectra of the all samples was quenched because the dopant complexes acted as non-radiative centers. While three emission bands located at 409 nm (3.03 eV), 496 nm (2.5 eV) and 513 nm (2.4 eV) were, respectively, observed from the PL spectra of the four samples. The three emission bands were in relation to Zn interstitials, Zn vacancies and the complex of V_O and Zn_i (V_OZn_i). The quantity of the Zn interstitials maintained invariable basically, while the quantity of the V_OZn_i slightly decreased as substrate temperature increased.     

Effect of oxidation temperature on microstructure, mechanical behaviors and surface morphology of nanocomposite Ti-Cx-Ny thin films

Two nanocomposite Ti-C_x-N_y thin films, TiC_0.95N_0.60 and TiC_2.35N_0.68, as well as one pure TiN, were deposited at 500 °C on Si(1 0 0) substrate by reactive unbalanced dc-magnetron sputtering. Oxidation experiments of these films were carried out in air at fixed temperatures in a regime of 250-600 °C with an interval of 50 °C. As-deposited and oxidized films were characterized and analyzed using X-ray diffraction (XRD), microindentation, Newton's ring methods and atomic force microscopy (AFM). It was found that the starting oxidation temperature of nanocomposite Ti-C_x-N_y thin films was 300 °C irrespective of the carbon content; however their oxidation rate strongly depended on their carbon content. Higher carbon content caused more serious oxidation. After oxidation, the film hardness value remained up to the starting oxidation temperature, followed by fast decrease with increasing heating temperature. The residual compressive stress did not show a similar trend with the hardness. Its value was first increased with increase of heating temperature, and got its maximum at the starting oxidation temperature. A decrease in residual stress was followed when heating temperature was further increased. The film surface roughness value was slightly increased with heating temperature till the starting oxidation temperature, a great decrease in surface roughness was followed with further increase of heating temperature.     

氦氢离子协同注入对锆膜形貌及物相结构的影响

采用磁控溅射法制备了Zr-Mo膜,随后在低能静电加速器上分别采用剂量为2.80×10¹⁷～1.12×10¹⁸ions·cm^-2的He⁺、H⁺离子辐照Zr-Mo膜,利用光学透镜、扫描电镜、原子力显微镜和X射线衍射研究He⁺、H⁺离子协同注入效应对Zr-Mo膜微观结构的影响。实验结果表明:原始Zr-Mo膜表层晶粒清晰可见,尺寸约为200nm;辐照效应可导致Zr-Mo膜表层产生微观损伤区域,在注He⁺基础上注H⁺导致Zr-Mo膜出现更为严重的损伤现象;离子注入的表面溅射效应可使膜面晶粒边界逐渐刻蚀退让,导致膜面更加光滑、细致;He⁺、H⁺离子协同注入可使Zr-Mo膜晶格发生畸变,注入期间未使Zr-Mo膜发生吸H相变生成氢化物。