Ion beam sputter deposition of TiO<Subscript>2</Subscript> films using oxygen ions

TiO₂ thin films were grown by ion beam sputter deposition (IBSD) using oxygen ions, with the ion energy and geometrical parameters (ion incidence angle, polar emission angle, and scattering angle) being varied systematically. Metallic Ti and ceramic TiO₂ served as target materials. The thin films were characterized concerning thickness, growth rate, surface topography, structural properties, mass density, and optical properties. It was found that the scattering geometry has the main impact on the film properties. Target material, ion energy, and ion incidence angle have only a marginal influence. Former studies on reactive IBSD of TiO₂ using Ar and Xe ions reported equivalent patterns. Nevertheless, the respective ion species distinctively affects the film properties. For instance, mass density and the refractive index of the TiO₂ thin films are remarkably lower for sputtering with oxygen ions than for sputtering with Ar or Xe ions. The variations in the thin film properties are tentatively attributed to the angular and the energy distribution of the film-forming particles, especially, to those of the backscattered primary particles.     

Correlation of process parameters and properties of TiO<Subscript>2</Subscript> films grown by ion beam sputter deposition from a ceramic target

The correlation between process parameters and properties of TiO₂ films grown by ion beam sputter deposition from a ceramic target was investigated. TiO₂ films were grown under systematic variation of ion beam parameters (ion species, ion energy) and geometrical parameters (ion incidence angle, polar emission angle) and characterized with respect to film thickness, growth rate, structural properties, surface topography, composition, optical properties, and mass density. Systematic variations of film properties with the scattering geometry, namely the scattering angle, have been revealed. There are also considerable differences in film properties when changing the process gas from Ar to Xe. Similar systematics were reported for TiO₂ films grown by reactive ion beam sputter deposition from a metal target [C. Bundesmann et al., Appl. Surf. Sci. 421, 331 (2017)]. However, there are some deviations from the previously reported data, for instance, in growth rate, mass density and optical properties.     

离子束增强沉积制备p型氧化锌薄膜及其机理研究

采用离子束增强沉积方法在Si和SiO₂/Si衬底上制备In-N共掺杂ZnO薄膜(INZO)，溅射靶是用ZnO和2 atm% In₂O₃粉体均匀混合并压制而成，在氩离子溅射ZnO靶的同时，氮、氩混合离子束垂直注入沉积的薄膜.实验结果显示INZO薄膜具有(002)的择优取向，并且为p型导电，电阻率最低为0.9Ωcm.薄膜在氮气、氧气气氛下退火，对薄膜的结构和电学特性与成膜和退火条件的关系进行了分析. 关键词： 氧化锌薄膜 p型掺杂 离子束增强沉积     

Growth of Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> films on the Si(111) surface covered by a thin SiO<Subscript>2</Subscript> layer

Magnetite polycrystalline films are grown by variously oxidizing a Fe film on the Si(111) surface covered by a thin (1.5 nm) SiO₂ layer. It is found that defects in the SiO₂ layer influence silicidation under heating of the Fe film. The high-temperature oxidation of the Fe film results in the formation of both Fe₃O₄ and iron monosilicide. However, the high-temperature deposition of Fe in an oxygen atmosphere leads to the growth of a compositionally uniform Fe₃O₄ film on the SiO₂ surface. It is found that such a synthesis method causes [311] texture to arise in the magnetite film, with the texture axis normal to the surface. The influence of the synthesis method on the magnetic properties of grown Fe₃O₄ films is studied. A high coercive force of Fe₃O₃ films grown by Fe film oxidation is related to their specific morphology and compositional nonuniformity.     

Study on the orientation of silver films by ion-beam assisted deposition

Low energy ion beam assisted deposition (IBAD) was employed to prepare Ag films on Mo/Si (100) substrate. It was found that Ag films deposited by sputtering method without ion beam bombardment were preferred (111) orientation. When the depositing film was simultaneously bombardment by Ar⁺ beam perpendicular to the film surface at ion/atom arrival ratio of 0.18, the prepared films exhibited weak (111) and (200) mixed orientations. When the direction of Ar⁺ beam was off-normal direction of the film surface, Ag films showed highly preferred (111) orientation. Monte Carlo method was used to calculate the sputtering yields of Ar⁺ ions at various incident and azimuth angles. The effects of channeling and surface free energy on the crystallographic orientation of Ag films were discussed.     

Photocatalytic properties of nanocrystalline TiO<Subscript>2</Subscript> thin films doped with Tb

In this work photocatalytic properties of TiO₂ thin films doped with different amount of Tb have been described. Thin films were prepared by high energy reactive magnetron sputtering process. Comparable photocatalytic activity has been found for all doped TiO₂ thin films, while different amounts of Tb dopant (0.4 and 2.6 at. %) results in either an anatase or rutile structure. It was found that the terbium dopant incorporated into TiO₂ was also responsible for the amount of hydroxyl groups and water particles adsorbed on the thin film surfaces and thus photocatalytic activity was few times higher in comparison with results collected for undoped TiO₂ thin films.     

Thermal characterization of TiC<Subscript>x</Subscript>O<Subscript>y</Subscript> thin films

Thermal wave characterization of thin films used in industrial applications can be a useful tool, not just to get information on the films' thermal properties, but to get information on structural-physical parameters, e.g. crystalline structure and surface roughness, and on the film deposition conditions, since the thermal film properties are directly related to the structural-physical parameters and to the deposition conditions. Different sets of TiC_XO_Y thin films, deposited by reactive magnetron sputtering on steel, have been prepared, changing only one deposition parameter at a time. Here, the effect of the oxygen flow on the thermal film properties is studied. The thermal waves have been measured by modulated IR radiometry, and the phase lag data have been interpreted using an Extremum method by which the thermal coating parameters are directly related to the values and modulation frequencies of the relative extrema of the inverse calibrated thermal wave phases. Structural/morphological characterization has been done using X-ray diffraction (XRD) and atomic force microscopy (AFM). The characterization of the films also includes thickness, hardness, and electric resistivity measurements. The results obtained so far indicate strong correlations between the thermal diffusivity and conductivity, on the one hand, and the oxygen flow on the other hand.     

Effect of ion treatment on the structure and optical properties of nanocrystalline In<Subscript>2</Subscript>O<Subscript>3</Subscript>:Sn films

Transparent conductive films of indium oxide doped with tin have been obtained by the reactive RF-magnetron sputtering method with ion treatment of the specimen during film condensation. Ion treatment of the oxide surface during the sputtering process leads to the formation of a preferred crystallite orientation, a decrease in the size of the coherent reflection areas and an increase in the optical transparency window.     

Femtosecond pulsed-laser deposition of BaTiO<Subscript>3</Subscript>

The elemental composition and the surface morphology of thin films grown by laser ablation of barium titanate with femtosecond pulses at 620 nm laser wavelength have been systematically studied according to the experimental pulsed-laser deposition parameters : laser energy density, oxygen pressure, substrate temperature, target–substrate distance and substrate position (in- and off-axis geometry). Firstly, even at high temperature (700 °C), the deposits consist of coalesced particles up to 1-μm in size, mixed in a poorly crystallised tetragonal BaTiO₃ thin film. The particles formed in femtosecond pulsed-laser deposition induce a high surface roughness, which is observed whatever the experimental growth conditions and does not correspond to the droplets often observed during laser ablation in the nanosecond regime. As shown by plasma expansion dynamics, these particles propagate toward the substrate in the plasma plume with a low velocity, and are assumed to be produced by gas-phase reactions. Moreover, the cationic concentration evaluated through the Ba/Ti ratio strongly depends on the oxygen pressure in the ablation chamber and the angular position of the substrate along the normal to the target at laser impact. Indeed, the films appear to be enriched in the heavy element (Ba) when the substrate is located at high angular deviation. This fact is correlated to an increase in the lighter species (i.e. Ti) in the central part of the plasma plume. Received: 30 April 2002 / Accepted: 26 August 2002 / Published online: 8 January 2003 RID="*" ID="*"Corresponding author. Fax: +33-1/4354-2878, E-mail: millon@gps.jussieu.fr RID="**" ID="**"Also at: LSMCL, Université de Metz, 57078 Metz Cedex 3, France     

Plasma‐Substrate Interaction during Plasma Deposition on Polymers

The initial stage of film growth during plasma deposition on polymers determines many film properties such as morphology and structure, interphase formation and adhesion. Therefore, the plasma‐substrate interaction is investigated regarding the energy density during film growth, which is defined by the energy flux per depositing atom. The flux of film‐forming species and the flux of energetic particles were determined for metal sputtering (silver films) and plasma polymer deposition (amino‐functional hydrocarbon films). It is shown that enhanced energy densities can be obtained during the initial film growth due to reduced deposition rates and mixing with the polymer substrate (interphase formation). Thus, good adhesion on polymers such as polyethylene terephthalate (PET) has been achieved. (© 2014 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effect of composition and thermal treatment on the properties and microstructure of Co–SiO<Subscript>2</Subscript> films

The effect of various physical factors (chemical composition, temperature, and thermal treatment) on the macroscopic properties of Co–SiO₂ film composites produced by ion-plasma sputtering of mosaic targets has been investigated. The microstructure parameters have been estimated indirectly by analyzing the magnetization curves and the temperature dependence of magnetization. It has been concluded that the model of homogeneous noninteracting superparamagnetic particles of hexagonal Co is applicable for describing the magnetic properties of the film composites under study over a rather wide range of compositions.     

X-ray photoemission study of MgB<Subscript>2</Subscript> films synthesized from in-situ annealed MgB<Subscript>2</Subscript>/Mg multilayers

Superconducting MgB₂ films were obtained by in-situ annealing of precursor multilayers deposited at low substrate temperature by sputtering from a MgB₂ stoichiometric target and by thermal evaporation of pure Mg. After an in-situ annealing at 500–600 °C, the films showed a zero resistance critical temperature up to 31 K. The as-obtained MgB₂ films were investigated by X-ray photoelectron spectroscopy (XPS) and X-ray auger electron spectroscopy (XAES). The electronic structure was studied by monitoring the B 1s, Mg 2p, O 1s core-levels and the Mg KL₂L₃ Auger line. For comparison, the electronic structure of an MgB₂ commercial superconducting sputtering target, of a not-annealed precursor film and of a sample obtained by direct sputtering from the MgB₂ target have also been investigated. Electron spectroscopy showed that in the superconducting systems the Mg KL₂L₃ Auger line kinetic energy position is always higher by about 0.9 eV with respect to the energy position of the same Auger line measured in the non-superconducting samples. PACS 74.25Jb; 74.78.Bz; 74.70.Ad     

Room temperature deposition of amorphous SiC thin films using low energy ion bombardment

Silicon carbide (SiC) films are prepared by single- and dual-ion beam sputtering deposition at room temperature, respectively. An assisting argon ion beam (ion energy Ei=150 eV) bombards directly the substrate surface to modify the SiC film surface. The thin films are characterized by the Fourier transform infrared spectroscopy (FTIR) and the Raman spectra. With assisting ion beam bombardment, the density of the Si–C bond in the film increases. Meanwhile, the excess carbon or the size of the sp² bonded clusters and the amorphous Si (a-Si) phase decrease. These results indicate that the composition of the films is mainly Si–C bond. UV-vis transmission shows that the E_opt increases steadily from 1.85 eV for the amorphous SiC (a-SiC) films without bombardment to about 2.29 eV for those with assisting ion beam bombardment.     

离子束溅射制备Nb2O5光学薄膜的特性研究

研究了离子束溅射(IBS)制备的Nb₂O₅薄膜的光学特性、应力、薄膜微结构等特性,系统地分析了辅助离子源的离子束能量和离子束流对薄膜特性的影响.结果显示,在辅助离子源不同参数情况下,折射率在波长550 nm处为2.310—2.276,应力值为-281—-152 MPa.在合适的工艺参数下,消光系数可小于10^-4,薄膜具有很好的表面平整度.与用离子辅助沉积(IAD)制备的薄膜相比,IBS制备的薄膜具有更好的光学特性和薄膜微结构. 关键词： 2O₅薄膜')" href="#">Nb₂O₅薄膜 离子束溅射 光学特性 应力     

The Validity of the Results of High-Performance Modeling of SiO<Subscript>2</Subscript> Film Growth

This work is devoted to checking of the validity of the results of high-performance modeling of SiO₂ film growth. Modeling of the high-energy deposition process shows that the refractive indices of deposited SiO₂ films exceed the refractive index of a fused silica substrate. This is entirely supported by the analysis of spectrophotometric data obtained for practical thin films deposited using the respective deposition technique.     

Highly (100) oriented Pb(Zr<Subscript>0.52</Subscript>Ti<Subscript>0.48</Subscript>)O<Subscript>3</Subscript>/LaNiO<Subscript>3</Subscript> films grown on amorphous substrates by pulsed laser deposition

Pb(Zr_0.52Ti_0.48)O₃ (PZT)/LaNiO₃ (LNO) thin films with highly (100) out of plane orientation were produced on SiO₂/Si(100) and alkaline earth aluminosilicate glass substrates by pulsed laser deposition (PLD). Orientations of both PZT and LNO films were evaluated using X-ray diffraction. The pure (100)-oriented PZT/LNO films were obtained under optimized deposition conditions. Time of flight-secondary ion mass spectrometry analysis showed that LNO could effectively block interdiffusion between the PZT films and the substrates. Fairly smooth surfaces of the PZT films with roughness of about 4 nm were observed using an atomic force microscope. Cross sectional examination revealed that the films grew in columnar grains. The PZT films grown on both SiO₂/Si and glass substrates demonstrated very good ferroelectric characteristic at room temperature with remnant polarization of up to 26 μC/cm². PACS 79.20.DS; 77.84.DY; 78.70.Ck     

Optical properties of SrTiO<Subscript>3</Subscript> thin films by pulsed laser deposition

SrTiO₃ thin films were prepared on a fused-quartz substrate by pulsed laser deposition (PLD). Dense and homogeneous films with a thickness of 260 nm were prepared. Optical constants (refractive index n and extinction coefficient k) were determined from the transmittance spectra using the envelope method. The optical band gap energy of the films was found to be 3.58 eV, higher than the 3.22 eV for bulk SrTiO₃, attributable to the film stress exerted by the substrate. The dispersion relation of the refractive index vs. wavelength follows the single electronic oscillator model. The refractive index and the packing density for the PLD-prepared SrTiO₃ thin films are higher than those for the SrTiO₃ films prepared by physical vapor deposition, sol–gel and RF sputtering. Received: 18 March 2002 / Accepted: 7 October 2002 / Published online: 8 January 2003 RID="*" ID="*"Corresponding author. Fax: +86-25/359-5535, E-mail: mszhang@nju.edu.cn     

Absorption and photoluminescence properties of silver clusters in SiO<Subscript>2</Subscript> matrix

Absorption and luminescence properties of silver nanoclusters embedded in SiO₂ matrixes were studied experimentally. Thin SiO₂ films with different amount of silver were produced by co-deposition of Ag and SiO₂ onto the silica substrates in vacuum. The thus obtained films possess three peaks in absorption spectra at 297, 329 and 401 nm and two peaks in luminescence spectra at about 500 and 650 nm. We ascribed these spectral features to silver nanoclusters of different sizes that present in the film. Thermal annealing transforms both absorption and emission spectra of the films. Lager clusters that are formed after annealing possess one absorption band at 350–450 nm and one luminescence band at 510 nm. The luminescence was observed only in samples with the silver content of less than 2.2%. Quenching of the luminescence in samples with higher concentration of silver is due to the presence of larger particles with plasmonic properties.     

离子引出收集的沉积与溅射研究

研究离子引发收集过程中的沉积和溅射特性,给出了离子沉积和溅射的数理模型,其中重点分析了结合能、捕获概率和溅射系数这几个参数的物理意义和计算公式,给出了收集板总收集量和损失量.并且用计算机模拟了收集板的收集,给出不同的离子入射能量下入射离子元素沉积厚度和不同元素靶对各入射离子溅射特性的影响.得出以下的结论:随着离子沉积在收集板表面涂层厚度的增加溅射率也增加;离子的引出电压不是越高越好;轻质量离子的总收集率比较小;入射离子沉积和溅射特性和收集板靶原子质量有关,质量轻的金属材料作收集板,有利于提高离子的收集率. 关键词： 溅射 捕获概率 溅射概率     

Formation of Films of Tungsten and its Oxides in a High-Frequency Capacitive Discharge in a D<Subscript>2</Subscript>-O<Subscript>2</Subscript> Mixture

A technique for tungsten-film deposition on different substrates in asymmetrical high-frequency (1.76 MHz) capacitive discharge in a D₂?6.5 mol % O₂ mixture under a total pressure of 15 Pa and at 60–130°C is considered. A circular W strip near the upper inner edge of a cylindrical hollow cathode with a radius of 4.2 cm and a height of 10 cm is the source of W particles. The smooth transition from sputtering of the inner surface to deposition occurs at a distance of about 4 cm from the upper boundary of the open part of the cathode. W, Mo, ZrO₂, Si, and Cu substrates are placed in the lower closed end (bottom) and on the inner lateral cathode surface. At the upper cathode edge the sputtering yield is (4–5) × 10^?2 at/ion. The mass rate of W deposition on the cathode bottom does not depend on the substrate type and is 40 μg/(cm² h). The peculiarities of the composition, morphology, and structure of W films obtained on the lateral surface and bottom of the hollow cathode are discussed.