Microstructure and mechanical properties of pulsed DC magnetron sputtered nanocomposite Cr-Cu-N thin films

The nanocomposite Cr-Cu-N thin films have been deposited at a substrate temperature of 250 °C by a bipolar asymmetric pulsed DC reactive magnetron sputtering process. Different Cu contents ranging from 0.4 to 14.9 at.% were achieved. The structures of Cr-Cu-N thin films were analyzed by XRD. The surface and cross sectional morphologies of thin films were examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The nanoindentation and scratch tests were adopted to evaluate the mechanical and tribological properties of Cr-Cu-N coatings. The influences of Cu content on the structure, mechanical and tribological properties of Cr-Cu-N coatings were explored. It is observed that the columnar structure no longer exists when the Cu content exceeds 10.9 at.%. The stability of CrN phase in the coating is influenced by the Cu content. The scratching coefficient of thin films decreases with increasing Cu content. Sufficient adhesion and tribological properties of Cr-Cu-N coatings are achieved. The maximum average hardness around 20 GPa and scratching coefficient around 0.1 are found in the coatings with around 2.1 to 2.6 at.% Cu in this work.     

RF magnetron sputtered ITO:Zr thin films for the high efficiency a-Si:H/c-Si heterojunction solar cells

ITO and ITO:Zr films with various thicknesses were prepared on glass substrates by RF magnetron sputtering. We observed a decrease in sheet resistance with increasing film thickness that in good agreement with Fuchs-Sondheimer theory. The ITO films doped with ZrO₂ (～0.2 wt%) showed improvement in some of the electrical and optical properties of ITO films. The surface roughness of ITO:Zr films increased with increasing film thickness. ITO:Zr films with thickness of 120 nm showed highest work function of 5.13 eV, as estimated from XPS data. The ITO:Zr films were employed as front electrodes in HIT solar cells; the best device performance was found to be: V_oc = 710 mV, J_sc = 34.44 mA/cm², FF = 74.8%, η = 18.30% at a thickness of 120 nm. A maximum quantum efficiency (QE) of 89% was recorded for HIT solar cells at a wavelength of 700 nm for 120 nm thick ITO:Zr films.     

Properties of magnetron sputtered Al-Si-N thin films with a low and high Si content

The article reports on properties of Al-Si-N films with a low (≤ 10 at.%) and high (≥ 25 at.%) Si content reactively sputtered using a closed magnetic field dual magnetron system operated in ac pulse mode. The films were sputtered from a composed target (a Si plate fixed by an Al ring with inner diameter Ø_i = 15 or 26 mm). Main attention was devoted to the investigation of a relationship between the structure of the films and their mechanical properties, thermal stability of hardness, and oxidation resistance. It was found that (1) while the films with a low (≤ 10 at.%) Si content are crystalline (c-(Al-Si-N)), those with a high (≥ 25 at.%) Si content are amorphous (a-(Al-Si-N)) when sputtered at the substrate temperature T_s = 500 °C, (2) both groups of the films exhibit (i) a high hardness H = 21 and 25 GPa, respectively, and high values of the oxidation resistance exceeding 1000 °C; 1100 °C (Δm = 0 mg/cm²) and 1300 °C (Δm ≈ 0.003 mg/cm²), respectively, (3) the hardness of a-(Al-Si-N) does not vary with increasing annealing temperature T_a up to 1100 °C even after 4 h, and (4) a high oxidation resistance of c-(Al-Si-N) film with a low (< 10 at.%) Si content is due to the formation of a dense, nearly amorphous Al₂O₃ surface layer which is formed in reaction of free Al atoms with ambient oxygen and prevents the fast penetration of oxygen into bulk of the film. Obtained results contribute to understand the effect of Al and Si in the Al-Si-N thin film on its mechanical properties, thermal stability and oxidation resistance.     

In-situ TEM tensile testing of DC magnetron sputtered and pulsed laser deposited Ni thin films

Two nanocrystalline Ni thin films, one prepared via DC Magnetron Sputtering and the other prepared via Pulsed Laser Deposition, were strained in-situ in the Transmission Electron Microscope. Although the grain sizes were similar, the two films behaved quite differently in tension. The sputtered material was found to behave in a brittle manner, with failure occurring via rapid coalescence of intergranular cracks. Conversely, the laser deposited film behaved in a ductile manner, with failure occurring by slow ductile crack growth. The difference in failure mechanism was attributed to the presence of grain boundary porosity in the sputtered thin film. Both films exhibited pervasive dislocation motion before failure, and showed no conclusive evidence of a change in deformation mode.     

Surface discharge characteristics of MgO thin films prepared by RF reactive magnetron sputtering

This paper describes the surface glow-discharge effect of MgO thin films prepared by reactive radio-frequency planar magnetron sputtering on the dielectric layer of an alternating-current plasma display panel. By introducing an MgO coating on the dielectric the discharge voltage decreases sharply, although the thickness is only a few tens of Ångstroms. The lowest discharge voltage is obtained for the sample prepared at a 30% O₂ content in an O₂+Ar gas mixture and at a sputtering gas pressure of about 5 mTorr. Moreover, high transparency (95%) is also obtained under the same experimental conditions. The samples prepared show more sputter-resistant properties than samples prepared by the electron-beam method and no cracks are observed on the surface after post-deposition annealing.     

Growth morphology and corrosion resistance of magnetron sputtered Cr films

Chromium (Cr) films are commonly used as corrosion-resistant coatings because they form a passive protective scale. The film morphology and microstructure are important aspects of corrosion resistance. This paper presents growth mechanisms and morphologies of these films to provide insight into correlation between microstructure and corrosion resistance. Thin films of Cr were deposited on silicon wafers, and AISI 1018 carbon steel substrates using a plasma-enhanced magnetron sputtering technique. A tungsten filament was used to produce a plasma that enhances ion bombardment on the workpiece during the magnetron sputter deposition process. The deposited films were characterized by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. The film growth morphology and microstructure are correlated with sample orientation (with respect to the magnetron) and the deposition parameters. One important deposition parameter affecting Cr film properties is the level of plasma ion bombardment. This investigation demonstrated that at a low level of ion bombardment, a columnar structure is formed with large column widths resulting in a film that is discontinuous. As the level of ion bombardment increases, the films become denser and more continuous. Using the filament induced plasma enhancement method, a fully dense chromium film without indication of columnar structure was achieved. The corrosion behavior of the deposited films was studied using potentiodynamic polarization techniques. This study demonstrated that adequate ion bombardment is necessary to achieve good corrosion resistance.     

Characterization of magnetron sputtered rhodium films for reflective coatings

Preparation and detailed characterization of metallic rhodium films prepared by magnetron sputtering on silicon substrates have been carried out. Different deposition conditions such as gas pressure, deposition rate and substrate temperature were investigated. The films were characterized by XPS, SEM, XRD, AFM and reflectivity measurements. No impurities were detected on the surface after deposition. The films have a low roughness and their structure exhibit nanometric crystallites with a dense columnar structure. Amongst all investigated parameters, only the gas pressure during deposition was observed to have an influence on the optical properties of the film. Otherwise, the measured reflectivity is close to the reflectivity calculated from optical constants of pure rhodium films.     

Effects of annealing atmosphere on the structural and electrical properties of (Na0.5K0.5)NbO3 thin films grown by RF magnetron sputtering

Amorphous (Na_0.5K_0.5)NbO₃ (NKN) thin films were grown at 300 °C and subsequently annealed at 800 °C under Na₂O, K₂O and NKN atmospheres. When the annealing time was less than 50 min, K₆Nb_10.88O₃₀ and Na₂Nb₄O₁₁ secondary phases were formed in all the films. Moreover, they were also found in films annealed at 750 °C for 180 min under NKN atmosphere, indicating that they were transient phases formed when the sintering time and temperature were not sufficient. For the film annealed for 50 min under Na₂O atmosphere, an Na-excess (Na_1?xK_x)NbO₃ (N_1?xK_xN) phase was formed, whereas a K-excess N_1?xK_xN phase was developed in the film annealed under K₂O atmosphere. On the other hand, a homogeneous NKN phase was developed in the film annealed under NKN atmosphere and this was maintained after a long period (100 min) of annealing at 800 °C. A high leakage current density and a small dielectric constant (ε_r) were observed for films annealed under Na₂O and K₂O atmospheres due to the evaporation of K₂O and Na₂O, respectively. Moreover, they exhibited a small remnant polarization (P_r) and a small coercive electric field (E_c). On the other hand, the film annealed under NKN atmosphere exhibited a very low leakage current density of 2.6 × 10^?9 A cm^?2 at 0.2 MV cm^?1 and had good ferroelectric and piezoelectric properties of ε_r = 620, P_r = 11.7 μC cm^?2, E_c = 133.8 kV cm^?1 and d₃₃ = 74 pm V^?2 at 50 kV cm^?1.     

磁控溅射Al-Fe-Sn 薄膜的电输运性能

在电子工业中,为了制备低电阻率的Al合金薄膜,需要对薄膜进行退火。虽然材料的电阻率与其电输运性能密切相关,然而目前为止,对于铝合金薄膜的电输运性能研究甚少。 本文首先利用TEM对于磁控溅射铝合金薄膜的结构,特别是与基底界面处的结构进行了表征。在此基础上,利用霍尔效应测试了解界面状态的变化对于霍尔载流子浓度及迁移率的影响。 我们实验的结果表明, 在退火的过程中,薄膜与下层基底之间通过扩散过程形成紧密接触,从而使得合金薄膜同时具有较高的载流子浓度以及载流子迁移率。最后,利用一个新提出的能带模型,解释所观察到的界面变化对于电导率的影响。     

Structural, electrical and mechanical properties of magnetron sputtered NiTi/PZT/TiOx thin film heterostructures

Shape memory alloy (NiTi) thin films coupled to ferroelectric lead zirconate titanate (PZT) produce an intelligent material capable of performing both sensing and actuating functions. In the present study, we report on the in-situ growth of NiTi/PZT/TiO_x heterostructure on Pt/Ti/SiO₂/Si substrates using magnetron sputtering technique. Deposition processing, microstructure, surface morphology, electrical properties and mechanical properties of these heterostructures were systematically investigated. The top NiTi films exhibit austenitic B2 structure with preferred (110) orientation. The varying thickness of NiTi films had a significant influence on properties of NiTi/PZT/TiO_x heterostructure. The bottom TiO_x layer was observed to favor the growth of perovskite PZT films with (100) orientation. Nanoindentation tests of these heterostructures were performed at room temperature. The mechanical hardness of the top NiTi layer of lower thickness was found to be highly influenced by underneath PZT layer. The heterostructure exhibited an interesting martensite to austenite phase transformation and polarization-electric field hysteresis behavior with remanent polarization (P_r) and the coercive field (E_r) of 17.1 μC/cm² and 69.6 kV/cm, respectively. These heterostructures having a layer of SMA material coupled to a ferroelectric material with underneath TiO_x layer are of immense technological importance for MEMS devices.     

Influence of oxygen gas content on the structural and optical properties of ZnO thin films deposited by RF magnetron sputtering at room temperature

Zinc oxide (ZnO) thin films were deposited on sapphire (0001) substrates at room temperature by radiofrequency (RF) magnetron sputtering at oxygen gas contents of 0%,25%,50% and 75%,respectively.The influence of oxygen gas content on the structural and optical properties of ZnO thin films was studied by a surface profile measuring system,X-ray diffraction analysis,atomic force microscopy,and UV spectrophotometry.It is found that the size of ZnO crystalline grains increases first and then decreases with the increase of oxygen gas content,and the maximum grain size locates at the 25% oxygen gas content.The crystalline quality and average optical transmittance (>90%) in the visible-light region of the ZnO film prepared at an oxygen gas content of 25% are better than those of ZnO films at the other contents.The obtained results can be attributed to the resputtering by energetic oxygen anions in the growing process.     

Structural characteristics and optical properties of plasma assisted reactive magnetron sputtered dielectric thin films for planar waveguiding applications

Thin films of aluminum oxide (Al₂O₃), tantalum pentoxide (Ta₂O₅), titanium oxide (TiO₂), yttrium oxide (Y₂O₃) and zirconium oxide (ZrO₂) were deposited by plasma assisted reactive dual magnetron sputtering to determine their suitability as a host for a rare earth doped planar waveguide upconversion laser. The effect of deposition parameters such as cathode, plasma power and oxygen gas flows were studied and the operational working points were determined. Both power and lambda control were used to optimize the optical quality of each material. By using lambda control feedback system, the magnetron power fluctuates to sustain a fixed oxygen flow in the target area reducing the compound layer growth on the material and maintaining a healthy deposition rate. The optical properties, structure and crystalline phase of each film were found to be dependent on the process parameters. X-ray diffraction (XRD) analysis revealed that the thin films varied from amorphous to highly crystalline depending on the deposition conditions. X-ray photoelectron spectroscopy (XPS) was utilized for surface compositional analysis revealing that films had varying stoichiometric ratios which are controlled for each material by the deposition parameters chosen. The waveguide loss for the thin film layers was investigated and Ta₂O₅ was shown to have a slab waveguide loss of ~ 1 dB/cm at both visible and infra-red wavelengths making it ideal for planar waveguide and laser applications. TiO₂, Y₂O₃ and ZrO₂ were found to deposit in a highly crystalline phase. Waveguiding in the TiO₂ layers was not possible at 633 nm or in the infrared region. The Y₂O₃ samples gave low loss (2–4 dB/cm) at the 1.3 and 1.5 μm wavelengths but no waveguiding at 633 nm or 833 nm was possible. Atomic force microscopy showed rough surface topography for TiO₂, Y₂O₃ and ZrO₂ akin to their crystalline growth with the SEM images confirming the regular crystalline columnar structure for the case of Y₂O₃ and ZrO₂.     

Microstructural characterizations of magnetron sputtered Ti films on glass substrate

Magnetron sputtered Ti thin films deposited on glass substrates under varying deposition parameters were characterized by X-Ray Diffraction, Scanning Electron Microscopy and Atomic Force Microscopy. The textures of the Ti films characterized by X-ray diffraction revealed the initial (1 0 0) preferred orientation but it transformed in to (0 0 2) and (1 0 1) orientation with increase in sputtering power and substrate temperature, respectively. The preferred orientations of (0 0 2) and (1 0 1) were observed for the films deposited with the sputtering pressure of 5 mTorr and 20 mTorr, respectively. The average surface roughness of the Ti films showed an increasing trend with power, pressure, and temperature from the Atomic Force Microscopy analysis. The dense film morphology was observed in the Scanning Electron Microcopy images of Ti thin films deposited with higher substrate temperature (500 °C). X-ray diffraction analysis revealed that the grain size of the Ti thin films exhibits an increasing trend with varying deposition parameters.     

Effect of assistant RF plasma on structure and properties of SiCN thin films prepared by RF magnetron sputtering of SiC target

Silicon carbon nitride thin films were deposited on Si(1 0 0) substrate at room temperature with different working pressure. The bonding structure and hardness were studied by means of X-ray photoelectron spectroscopy (XPS) and nano-indentation technique. The results showed that the assistant ratio-frequency (RF) plasma had a great effect on the structure and property of the films. The hardness values of the films prepared with assistant RF plasma were higher than those of the films prepared without it. Assisted with RF plasma, sp³C–N bond can be found in the film prepared at low working pressure, and the diamond C–C bond can be easily formed in the film prepared at higher working pressure.     

Microstructure, mechanical and electrochemical properties evaluation of pulsed DC reactive magnetron sputtered nanostructured Cr-Zr-N and Cr-Zr-Si-N thin films

Cr-Zr-Si-N thin films with various Zr contents were deposited by a bipolar asymmetric pulsed DC reactive magnetron sputtering system. In addition, a Cr-Zr-N film without Si addition was fabricated as a reference. The influence of Zr on the constitution, microstructure, mechanical, tribological and electrochemical properties of Cr-Zr-Si-N films was investigated. The microstructure of thin films was determined by a glancing angle X-ray diffractometer (GA-XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. A nanoindenter, a Vickers micro hardness tester and pin-on-disk wear tests were adopted to evaluate the hardness, toughness and tribological properties of thin films, respectively. The electrochemical properties of thin films were also evaluated in 3.5 wt.% NaCl aqueous solution. In case of the Cr-Zr-Si-N films, the Si content was fixed around 6-8 at.% and various Zr contents ranging from 0.5 to 13.6 at.% were achieved by changing the Zr target power density. In comparison to the Cr-Zr-N reference film, the addition of ~ 7.0 at.% Si in Cr-Zr-Si-N films resulted in a refined columnar structure and enhanced mechanical and anti-corrosion properties. A lattice constant expansion of these films was observed with increasing Zr content. A nanostructured thin film with around 5-10 nm grain size was obtained in case of a Cr-13.6 at.% Zr-6.8 at.% Si-N film. In general, the hardness, plastic deformation resistance and corrosion resistance increased also with increasing Zr content in the Cr-Zr-Si-N films. The Cr-Zr-Si-N film containing 13.6 at.% Zr exhibited a combination of high hardness, good mechanical properties, adequate tribological performance and excellent corrosion resistance in this study.     

Preparation and optoelectronic properties of a-IGZO thin films deposited by RF magnetron sputtering at different working pressures

Transparent oxide semiconductor, a-IGZO, thin films were prepared by high-vacuum RF magnetron sputtering at different working pressures. The effect of working pressure on crystal structure, surface morphology, and electrical and optical properties of the films was studied.The highest hall mobility of 17.45 cm~2·V~(-1)·s~(-1) is obtained at 0.3 Pa with annealing at 200 ℃, while the highest carrier concentration of 2.32× 1020 cm~(-3) and the lowest resistivity of 0.001568 Ω-cm are obtained at 0.45 Pa with annealing. The highest transmittance of 90.9 % is obtained at 0.9 Pa with annealing treatment. A "blue shift" of UV absorption edge is observed with the increase of working pressure.     

Characterization and analysis of DLC films with different thickness deposited by RF magnetron PECVD

Diamond-like carbon (DLC) films have excellent mechanical and chemical properties similar to those of crystalline diamond giving them wide applications as protective coatings. So far, a variety of methods are employed to deposit DLC films. In this study, DLC films with different thicknesses were deposited on Si and glass substrates using RF magnetron PECVD method with C4H10 as carbon source. The bonding microstructure, surface morphology and tribological properties at different growing stages of the DLC films were tested. Raman spectra were deconvoluted into D peak at about 1370 cm-1 and G peak around 1590 cm-1, indicating typical features of the DLC films. A linear relationship between the film thickness and the deposition time was found, revealing that the required film thickness may be obtained by the appropriate tune of the deposition time. The concentration of sp3 and sp2 carbon atoms in the DLC films was measured by XPS spectra. As the films grew, the sp3 carbon atoms decreased while sp2 atoms increased. Surface morphology of the DLC films clearly showed that the films were composed of spherical carbon clusters, which tended to congregate as the deposition time increased. The friction coefficient of the films was very low and an increase was also found with the increase of film thickness corresponding to the results of XPS spectra. The scratch test proved that there was good bonding between the DLC films and the substrates.     

磁控溅射Al-Zr薄膜在微拉深成形中的拉深性能(英文)

拉深成形可以用来制备形状复杂的零部件,甚至可达微加工水平。采用磁控溅射方法,在基底温度分别为310K和433K下,制备了厚度约为15μm的两种不同的AlZr薄膜。将这两种薄膜做为坯料,采用冲头直径为0.75mm的微拉深设备研究其拉深性能。虽然这两种材料在拉伸试验中显示出较小的最大应变,但还是成功地实现了微拉深成形。在基底温度为310K和433K制备的两种材料的极限拉深比分别为1.8和1.7。这些结果比先前采用AlSc合金的结果要好,与采用传统轧制方法所得纯铝薄膜的拉深结果相似。结果表明,采用磁控溅射方法制备的薄膜可以用来进行微拉深成形。     

Optical and electrical properties of CuO thin films deposited at several growth temperatures by reactive RF magnetron sputtering

Copper oxide thin films were deposited on glass substrates at various growth temperatures by the reactive radio-frequency magnetron sputtering method. The band gap energy, carrier concentration and figure of merit of the CuO thin films were found to depend significantly on the growth temperature. All of the CuO films, irrespective of growth temperature, showed a monoclinic structure with the main CuO $\left( {\bar 111} \right)$ orientation, and the crystallite size, determined by using Scherrer’s formula, was about 50 nm for the thin film deposited at 25 °C. The highest figure of merit occurred for the film grown at 300 °C with an optical transmittance of 62.9% in the wavelength range of 800–1100 nm. The results suggest that the optimum growth temperature for growing high-quality CuO thin films is 300 °C.