BaTiO3 thin film prepared by coating-pyrolysis process on Nb-doped SrTiO3 substrate

Epitaxial BaTiO3 thin film was prepared on Nb-doped SrTiO3 substrate by coating-pyrolysis process using a mixed solution of barium and titanium naphthenates. The amorphous film pyrolyzed at 470 °C was crystallized with high orientation after heat-treatment at 850 °C under low oxygen partial pressure. X-ray diffraction /2 and scans indicated that the BaTiO3 film was epitaxial relationship with Nb-doped SrTiO3 substrate. The dielectric constant was approximately 230 at 103 Hz and was monotonically decreased with increasing of frequency at room temperature.     

The structures of low dielectric constant SiOC thin films prepared by direct and remote plasma enhanced chemical vapor deposition

Two structures of low dielectric constant (low-k) SiOC films were elucidated in this work. Low-k thin film by remote plasma mode was mainly composed of inorganic Si-O-Si backbone bonds and some oxygen atoms are partially substituted by CH₃, which lowers k value. The host matrix of low-k thin films deposited by direct plasma mode, however, was mainly composed of organic C-C bonds and “M” and “D” moieties of organosilicate building blocks, and thus the low dipole and ionic polarizabilities were the important factors on lowering k value.     

Characteristics of post-annealed SrTiO3 thin films prepared by mirror-confinement-type ECR plasma sputtering

SrTiO₃ films were synthesized on Pt/Ti/SiO₂/Si multilayer substrates by mirror-confinement-type ECR plasma sputtering without substrate heating. All films were found to be well crystallized at a substrate temperature below 450 K. A low temperature post-annealing of the films by electromagnetic-wave radiation drastically improved the crystallographic and electric properties of Pt/SrTiO₃/Pt/Ti/SiO₂/Si capacitors. The crystallinity of the films indicated little variation by post-annealing, but irradiation of electromagnetic wave was confirmed to be effective for decreasing the post-annealing time and temperature. The electric properties of films annealed without Pt upper electrodes were better than those with them, and the film dielectric constant reached a value of 260, which is nearly equal to thebulk one, at an annealing temperature of 573 K.     

阴极恒电流法制备SmS光学薄膜

以SmCl3·6H2O和Na2S2O3·5H2O为原料,采用电沉积法在单晶硅(100)和玻璃基板制备了SmS光学薄膜.采用XRD、AFM和紫外可见光分光光度计对薄膜进行了表征.研究了[Sm3 ]/[S2O32-]、溶液的pH值对于薄膜的物相的影响.结果表明:在[Sm3 ]/[S2O32-]=1:2,控制溶液pH值为4.50以及沉积1h的条件下,可制备出70nm厚单一晶相且表面比较平整的SmS薄膜,薄膜具有(331)方向的取向性.紫外光谱测试表明所制备的SmS薄膜具有290～300nm的紫外吸收特性,薄膜的禁带宽度约为3.6eV.     

BaTiO3/SrTiO3多层膜的制备及其介电性质

采用脉冲激光沉积法在Pt／Ti／SiO2／Si衬底上制备了BaTiO3／SrTiO3(BTO／STO)多层膜。XRD结果表明：多层膜呈现出明显的(110)择优取向,与Ba0.5Sr0．5TiO3单层膜相比,多层膜的相对介电常数得到了明显的增强,而介电损耗仍然保持在较低的水平。室温下频率为10kHz时,BTO／STO(n=6)多层膜的相对介电常数为506,而介电损耗仅为0．033。薄膜的C-V特性研究表明：多层膜呈现出较好的电容调谐度。     

Synchrotron X-ray reflectivity study of high dielectric constant alumina thin films prepared by atomic layer deposition

High dielectric constant (high-k) gate dielectric alumina films were prepared with nanoscale thicknesses on p-type silicon substrates by atomic layer deposition (ALD) with alternating pulses of trimethyl aluminum, nitrogen, ozone and nitrogen, and some of them were further thermally annealed. These high-k gate dielectric films were characterized by synchrotron X-ray reflectivity (XR), and the XR data were quantitatively analyzed, providing the following structural parameters of each gate dielectric film: the surface roughness and interfacial roughness, the electron density profile, the number of layers, and the thickness of individual layers. These structural characteristics were then analyzed in detail by considering the ALD processing conditions and post-thermal annealing history.     

热处理对溶胶凝胶MoO3薄膜特性的影响

报道了以钼粉为原料,采用溶胶凝胶技术和旋转镀膜方法,制备MoO3纳米薄膜。采用TG-DSC分析、X射线衍射仪(XRD)、原子力显微镜(AFM)、红外光谱仪等方法分析了薄膜的特性。研究结果表明MoO3薄膜具有纳米颗粒结构,热处理使得MoO3颗粒长大,且表面平整度降低;XRD分析显示,250℃热处理的MoO3粉末已结晶(为α-MoO3),且沿(Ok0)方向取向强烈;随热处理温度的升高,MoO3微结构发生了相应的变化,Mo——O（2）、Mo——O（3）键振动吸收增强,且峰位移动。这些变化归因于热处理导致的MoO3颗粒形状、团聚状态的变化以及应变键的产生。     

Mechanical characterization of zeolite low dielectric constant thin films by nanoindentation

With semiconductor technologies continuously pushing the miniaturization limits, there is a growing interest in developing novel low dielectric constant materials to replace the traditional dense SiO₂ insulators. In order to survive the multi-level integration process and provide reliable material and structure for the desired integrated circuits (IC) functions, the new low-k materials have to be mechanically strong and stable. Therefore the material selection and mechanical characterization are vital for the successful development of next generation low-k dielectrics. A new class of low-k materials, nanoporous pure-silica zeolite, is prepared in thin films using IC compatible spin coating process and characterized using depth sensing nanoindentation technique. The elastic modulus of the zeolite thin films is found to be significantly higher than that of other low-k materials with similar porosity and dielectric constants. Correlations between the mechanical, microstructural and electrical properties of the thin films are discussed in detail.     

Preparation of high dielectric constant thin films of CaCu3Ti4O12 by sol-gel

Preparation of sol-gel derived CaCu₃Ti₄O₁₂ (CCTO) thin films using two different sols and their characterization including their dielectric response are reported. The properties of CCTO films depend heavily on solvents used to prepare the sols. Dielectric constant as high as ∼900 at 100 kHz could be obtained when acetic acid was used to prepare the sol; in contrast, use of hexanoic acid in the sol yielded films with a much lower dielectric constant. The variation in grain and grain boundary conductivities with temperature has been measured. Activation energies of 0.08 eV and 0.68 eV have been found for grain and grain boundary conduction, respectively.     

Structure and optical properties of WO3 thin films prepared by chemical vapour deposition

The structure and optical properties of polycrystalline WO₃ thin films, prepared by annealing of black tungsten layers produced by chemical vapour deposition onto fused quartz substrates, were determined. Three different annealing modes were used. X-ray diffraction spectra revealed that all the films consisted of WO₃ crystallized in the monoclinic form. The optical constants (n and k), the thickness and the density of the films were determined. The optical constants and the density varied as a function of annealing conditions and film thickness.The determined values of the optical constants and the film densities are in agreement with the results found in the literature.Electrochromism was observed in these compounds.     

The photoluminescence and optical constant of ZnSe/SiO2 thin films prepared by sol–gel process

In this paper, ZnSe/SiO₂ thin films were prepared by sol–gel process. X-ray diffraction results indicate that the phase structure of ZnSe particles embedded in SiO₂ thin films is sphalerite (cubic ZnS). The dependence of ellipsometric angle ψ on wavelength λ of ZnSe/SiO₂ thin films was investigated by spectroscopic ellipsometers. The optical constant, thickness, porosity and the concentration of ZnSe/SiO₂ composite thin films were fitted according to Maxwell–Garnett effective medium theory. The thickness of ZnSe/SiO₂ thin films was also measured by surface profile. The photoluminescence properties of ZnSe/SiO₂ thin films were investigated by fluorescence spectrometer. The photoluminescence results reveal that the emission peak at 487 nm (2.5 eV) excited by 395 nm corresponds to the band-to-band emission of sphalerite ZnSe crystal (2.58 eV). Strong free exciton emission and other emission peaks corresponding to ZnSe lattice defects are also observed.     

ZnO thin films prepared by a single step sol-gel process

ZnO thin films were prepared on fused silica from a single spin-coating deposition of a sol-gel prepared with anhydrous zinc acetate [Zn(C₂H₃O₂)₂], monoethanolamine [H₂NC₂H₄OH ] and isopropanol. Crystallization annealing was performed over the range 500 to 650 °C. X-ray analysis showed that thin films were preferentially orientated along the [002] c-axis direction of the crystal. The films had a transparency of greater than 85% in the visible region for sol-gels with a zinc content of up to 0.7 M and exhibited absorption edges at ∼ 378 nm. The optical band-gap energy was evaluated to be 3.298-3.306 eV. Photoluminescence showed a strong emission centered at ca. 380 nm along with a broad yellow-orange emission centered at ca. 610 nm. Single step sol-gel thin film deposition in the film thickness range from 80 nm to 350 nm was demonstrated. The effect of sol-gel zinc concentration, film thickness and crystallization temperature on film microstructure, morphology and optical transparency is detailed. A process window for single spin coating deposition of c-axis oriented ZnO discussed.     

Preparation of epitaxially grown LaSrCoO3 thin films on SrTiO3(100) substrates by the dipping-pyrolysis process

LaSrCoO₃ thin films were spin-coated onto SrTiO₃(100) substrates by the dipping-pyrolysis process. X-ray diffraction -2 scans and X-ray diffraction scans were used to determine the crystallinity and in-plane alignment behavior of the films. The X-ray diffraction pattern shows the film obtained by annealing at 800°C was highly oriented. The X-ray diffraction pole-figure analysis and reciprocal-space mapping (-2 scans) of the resulting film showed that the film comprising the pseudocubic phase had an epitaxial relationship with the SrTiO₃ substrate.     

Poly-crystalline silicon thin films prepared by plasma-assisted hot-wire chemical vapor deposition

A combination of hot-wire chemical vapor deposition (HWCVD) and RF plasma, referred to as plasma-assisted HWCVD (P-HWCVD) was used to prepare poly-crystalline silicon (poly-Si) thin films. The effects of the plasma on the film properties were studied by varying the RF power (P_w) from 0 to 40 W. The results indicate that, compared with that of HWCVD samples, the film crystalline fraction (X_c) is enhanced at low P_w assistance, whereas it decreases at higher P_w. The uniformity of the film thickness is considerably improved by introducing plasma. It is also found that the porosity of the film, indirectly detected from infrared spectra, is much reduced. Auger analysis of the tantalum filament used in the P-HWCVD process shows much lower silicon contamination than that in HWCVD.     

Nickel thin films prepared by chemical vapour deposition from nickel acetylacetonate

Nickel thin films were prepared by a low-temperature atmospheric-pressure chemical vapour deposition method. The raw material was nickel acetylacetonate. At a reaction temperature above 250 °C, polycrystalline nickel films can be obtained by hydrogen reduction of the raw material. The resistivity (8.1–13.3 cm) of the film was close to that of bulk nickel.     

Copper thin films prepared by chemical vapour deposition from copper dipivalylmethanate

Copper thin films were prepared by a low-temperature atmospheric-pressure chemical vapour deposition method. The raw material was copper dipivalylmethanate which is volatile and thermally stable. At a reaction temperature above 220°C, polycrystalline copper films can be obtained by hydrogen reduction of the raw material. The resistivity of the film was in the range 1.7–2.7 cm.     

Growth and dielectric properties of BaTiO3 thin films prepared by the microwave-hydrothermal method

Polycrystalline BaTiO₃ thin films were grown on Ti-covered polymer substrates at 80 °C using the microwave-hydrothermal technique. Onset of BaTiO₃ formation occurred almost instantaneously at 80 °C and complete film coverage was achieved within 2 min. Longer reaction time was necessary for extensive grain growth to achieve dense films. Good quality capacitor films were only achieved at 4 h reaction time but loss tangents were high. Film dielectric constant and dielectric loss values of as-grown M-H films decreased with longer reaction time. Oxygen plasma treatment improved loss tangents to 4% by removal of both absorbed moisture and lattice hydroxyls.     

生长温度对PLD原位生长SrTiO3薄膜结构与非线性介电性能的影响

采用脉冲激光沉积法 ( PLD ) 制备的Y1B2Cu3O7-x薄膜作为叉指底电极,然后生长 SrTiO3介质薄膜,形成叉指型压控电容结构。通过对 SrTiO3薄膜的原位生长温度与薄膜微观结构及非线性介电性能之间的关系研究,发现随生长温度的升高薄膜晶粒逐步增大然后变小,薄膜的介电常数可调率和本征介电损耗随晶粒大小的增大而增加,而非本征损耗则随晶粒取向的增加而减小。