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.     

基于小波变换Cu-W薄膜表面形貌表征与硬度值分散性评价

提出了一种基于小波变换描述薄膜表面形貌的方法.运用离散小波变换法研究磁控溅射Cu-W薄膜表面特征随溅射时间的演变.结果表明，Cu-W薄膜在溅射时间超过600s时才达到稳定.不同薄膜表面形貌的变化主要是由高频部分引起.薄膜的粗糙表面会引起纳米压入硬度值的分散，这种分散性可用基于小波变换的薄膜表面形貌多尺度分解评价. 关键词： Cu-W 薄膜 表面形貌 小波变换 纳米压入     

Specific features of morphology and the structure of nanocrystalline cubic silicon carbide films grown on a silicon surface

Physics of the Solid State - The composition, surface morphology, and crystal structure of nanocrystalline cubic silicon carbide films grown on a silicon surface through chemical conversion from...     

Preparation and atomic oxygen erosion resistance of silica film formed on silicon rubber by sol-gel method

Based on the characteristic that silicon coupling agents have the capability to develop ‘molecular bridge’ in the interface of organic materials and inorganic materials, silica films were prepared on the surface of flexible silicon rubber by sol-gel method and the optical transmittance of the sample before and after atomic oxygen irradiation was tested. The surface morphology and structure of silica films were investigated by scanning electronic microscope (SEM) and Fourier transformed infrared spectroscopy (FTIR). The results indicated that the silica sol could easily form a uniform thin film on the surface of silicon rubber pretreated by high concentration silicon coupling agents, and the inorganic silica films could combine with organic silicon rubber without obvious delamination on the interface.     

Morphology of heteroepitaxial β-SiC films grown on Si(111) through high-vacuum chemical vapor deposition from hexane vapors

The characteristics of cubic silicon carbide films grown on silicon through high-vacuum chemical vapor deposition (HVCVD) from hexane vapors are investigated using scanning probe microscopy and x-ray diffraction. The surface morphology and structure of the films are analyzed as a function of the thickness of the deposited films and the nature of the substrate (silicon, sapphire). The role of different diffusion fluxes arising in the structure and the related possible mechanisms of growth of β-SiC layers on silicon substrates are discussed.     

Preparation and characterizations of amorphous nanostructured SiC thin films by low energy pulsed laser deposition

Amorphous silicon carbide (SiC) thin films were deposited on silicon substrates by pulsed laser ablation at room temperature. Thicknesses and surface morphology of the thin films were characterized using optical profilers, atomic force and field emission scanning electron microscopy. Nanohardnes, modulus and scratch resistance properties were determined using XP nanoindenter. The results show that crack free, smooth and nanostructured thin films can be deposited using low laser energy densities.     

碳化硅薄膜脉冲激光晶化特性研究

采用XeCl准分子激光对非晶碳化硅(a-SiC)薄膜的脉冲激光晶化特性进行了研究.通过原子力显微镜（AFM）和Raman光谱技术对退火前后薄膜样品的形貌、结构及物相特性进行了分析.结果表明，选用合适的激光能量采用激光退火技术能够实现a-SiC薄膜的纳米晶化.退火薄膜中的纳米颗粒大小随着激光能量密度的增加而增大；Raman谱分析结果显示了退火后的薄膜的晶态结构特性并给出了伴随退火过程存在的物相分凝现象.根据以上结果并结合激光退火特性，对a-SiC的脉冲激光晶化机理进行了讨论. 关键词： 激光退火 晶化 碳化硅     

化学气相沉积中影蔽效应对硅薄膜表面形貌和微结构的影响

采用斜入射热丝化学气相沉积技术(OAD-HWCVD),研究了气流入射角度(θ)对氢化非晶硅(a-Si:H)薄膜表面和微结构的影响.实验发现,薄膜厚度为1μm时,均方根粗糙度与tanθ成指数关系;在入射角度为75°时,薄膜表面由自仿射表面转变为mound表面.采用拉曼谱和红外谱表征了硅薄膜的微结构随气流入射角度的变化.在薄膜转变为mound表面生长之前,随入射角度的增加,准局域的影蔽效应使得薄膜中微空洞的数目及尺寸增加,导致薄膜微结构因子升高、致密度下降、薄膜质量变差.在薄膜转变为mound表面生长之后,非局域的影蔽效应导致大尺度的空洞,同时薄膜中以Si-Hn(n 2)形式存在的氢增多.本文以非晶硅薄膜为例,结合标度理论,分析了薄膜生长过程中的表面形貌和微结构与影蔽效应的关系.     

The porous silicon morphology effect on the growth of electrodeposited FeNi alloy

In this work, we report on cathodic deposition of FeNi thin films into porous silicon (PS) formed on n-type Si. Macroporous and mesoporous silicon layers were formed at constant potential or current density. The electrodeposited thin films were characterized by Energy Dispersive Spectroscopy (EDS) and X-Ray Diffraction (XRD). The magnetic properties of the FeNi layers were investigated by hysteresis loops measurements. SEM images of the FeNi films indicate that tubular and granular forms were obtained depending on the porous silicon surface morphology. Moreover, the FeNi films compositions are found to depend on the porous silicon microstructure. Finally, the XRD spectra of the deposited films show the presence of FeNi (111) and FeNi (220) peaks. The FeNi (111) peak has been shown for all polarization potentials, in agreement with results reported in the literature.     

Measurement and analysis of the surface roughness of Ag film used in plasmonic lithography

The silver(Ag)/photoresist(PR)/Ag structure, widely used in plasmonic photolithography, is fabricated on silicon substrate. The surface roughness of the top Ag film is measured and analyzed systematically. In particular, combined with template stripping technology, the lower side of the top Ag film is imaged by an atomic force microscope. The topographies show that the lower side surface is rougher than the initial surface of the subjacent PR film, which is mainly attributable to the deformation caused by particle collisions during the deposition of the Ag film. Additionally, further measurements show that the Ag film deposited on the PR exhibits a flatter upper side morphology than that directly deposited on the silicon substrate. This is explained by the different growth modes of Ag films on different substrates. This work will be beneficial to morphology analysis and performance evaluation for the films in optical and plasmonic devices.     

Low temperature synthesis of SiC films by vacuum laser ablation and their characterization

Thin films of silicon carbide were grown on Si(100) substrate by pulsed laser ablation of powder-pressed target. The influence of substrate temperature on both structure and surface morphology of SiC films was studied by scanning electron microscopy, X-ray diffraction, and IR spectroscopy.     

Magnetochemical effects occurring upon treatment of the thin ferromagnetic film surface in an acidic medium

The results from magnetooptical studies of the influence of magnetochemical effects on the surface morphology and local magnetic properties of FeN alloy thin films and thin-film systems that consist of alternating silicon dioxide and FeN layers of submicron thickness, are shown. The dramatic influence of chemical etching on the surface morphology and magnetic characteristics of the investigated samples is revealed.     

Adjusting chemical bonding of hard amorphous CSixNy thin films by N*-plasma-assisted pulsed laser deposition

Hard amorphous carbon silicon nitride thin films have been grown by pulsed laser deposition (PLD) of various carbon silicon nitride targets by using an additional nitrogen RF plasma source on [100] oriented silicon substrates at room temperature. The influence of the number of laser shots per target site on the growth rate and film surface morphology was studied. Up to about 30 at. % nitrogen and up to 20 at. % silicon were found in the films by Rutherford backscattering spectroscopy (RBS) and X-ray photoelectron spectroscopy (XPS). The XPS of the films showed a clear correlation of binding energy to the variation of PLD parameters. The films show a universal hardness value up to 23 GPa (reference value for silicon substrate 14 GPa) in dependence on target composition and PLD parameters. The results emphasise the possibility of variation of chemical bonding and corresponding properties, such as nanohardness, of amorphous CSi_xN_y thin films by the plasma-assisted PLD process.     

外加磁场对磁控溅射制备氮化硅陷光薄膜的影响

在基底与靶材之间放置磁性强弱不同的永久磁铁来研究外加磁 场对磁控溅射制备氮化硅陷光薄膜的影响. 通过X射线衍射、原子力显微镜 (AFM) 以及紫外分光光度计分别测试了外加磁场前后所制备薄膜的组织结构、表面形貌和光学性能. 结果表明, 外加磁场后, 氮化硅薄膜依然呈现非晶结构; 但是表面形貌发生明显改变, 中心磁场1.50 T下, 薄膜表面为特殊锥状尖峰结构"类金字塔"的突起, 而且这些突起颗粒垂直于基底表面; 在 可见光及近红外范围内, 中心磁场1.50 T 下的薄膜样品平均透射率最大, 平均透射率达到90% 以上, 比未加磁场的样品提高了近1 倍, 具有很好的陷光特性. 关键词： 外加磁场 磁控溅射 氮化硅薄膜 陷光效应     

Surface smoothening mechanism of amorphous silicon thin films

An important concern in the deposition of thin hydrogenated amorphous silicon () films is to obtain smooth surfaces. Herein, we combine molecular-dynamics simulations with first-principles density functional theory calculations to elucidate the smoothening mechanism of plasma deposited thin films. We show that the deposition precursor may diffuse rapidly on the film surface via overcoordinated surface Si atoms and incorporate into the film preferentially in surface valleys, with activation barriers for incorporation dependent on the local surface morphology. Experimental data on smoothening and precursor diffusion are accounted for.     

In_2O_3:Sn中间层改善B掺杂ZnO薄膜的性能及其应用研究

金属有机化学气相沉积(MOCVD)法生长的掺硼氧化锌(BZO)薄膜,具有天然的"类金字塔"绒面结构,作为硅基薄膜太阳电池的前电极具有良好的陷光效果.但直接获得的BZO薄膜表面形貌过于尖锐,影响后续硅基薄膜材料生长质量及太阳电池的光电转换效率.本文设计了以一层超薄In2O3:Sn(ITO)薄膜(～4 nm厚度)作为中间层的多层膜,并通过对顶层BZO薄膜的厚度调制,改善BZO薄膜的表面特性,薄膜结构为:glass/底层BZO/ITO/顶层BZO.合适厚度的顶层BZO薄膜有助于获得类似"菜花状"形貌特征,尖锐的表面趋于"柔和",而较厚的顶层BZO薄膜仍然保持"类金字塔状"结构."柔和"的BZO薄膜表面结构有助于提高后续生长薄膜电池的结晶质量.将获得的新型"三明治"结构多层膜应用于p-i-n型氢化微晶硅(μc-Si:H)薄膜太阳电池,相比传统的BZO薄膜,电池的量子效率QE在500—800 nm波长范围提高了～10%,并且电池的Jsc和Voc均有所提高.     

Photothermal laser processing of thin silicon nanoparticle films: on the impact of oxide formation on film morphology

Photothermal laser processing of thin films of H-terminated silicon nanoparticles (Si NPs) is investigated. Ethanolic dispersions of Si NPs with an average diameter of 45 nm are spin-coated on silicon substrates yielding films with thicknesses ≤500 nm. Small-area laser processing is carried out using a microfocused scanning cw-laser setup operating at a wavelength of 532 nm and a 1/e laser spot size of 1.4 μm. In conjunction with microscopic techniques, this provides a highly reproducible and convenient approach in order to study the dependence of the resulting film morphology and composition on the experimental parameters. Processing in air results in strongly oxidized granular structures with sizes between 100 and 200 nm. The formation of these structures is dominated by surface oxidation. In particular, changing the processing parameters (i.e., laser power, writing speed, and/or the background air pressure) has little effect on the morphology. Only in vacuum at pressures <1 mbar, oxygen adsorption, and hence oxide formation, is largely suppressed. Under these conditions, irradiation at low laser powers results in mesoporous surface layers, whereas compact silicon films are formed at high laser powers. In agreement with these results, comparative experiments with films of H-terminated and surface-oxidized Si NPs reveal a strong impact of the surface oxide layer on the film morphology. Mechanistic aspects and implications for photothermal processing techniques, e.g., targeting photovoltaic and thermoelectric applications, are discussed.     

Growth and characterization of β-SiC films obtained by fs laser ablation

We achieved the growth of cubic silicon carbide (SiC) films on (1 0 0)Si substrates by pulsed laser deposition (PLD) at moderate temperatures such as 750 °C, from a SiC target in vacuum. The as-deposited films are morphologically and structurally characterized by scanning electron microscopy (SEM), conventional and high-resolution transmission electron microscopy (TEM/HRTEM). The morphology of deposited films is dominated by columns nucleated from a thin nanostructured beta silicon carbide (β-SiC) interface layer. The combined effects of columnar growth, tilted facets of the emerging columns and the presence of particulates on the film surface, lead to a rather rough surface of the films.     

Optical anisotropy of copper dipivaloylmethanate molecular films

The structures of films obtained from a coordination compound, copper dipivaloylmethanate, and by vacuum vapor deposition onto single crystal silicon substrates are studied. The size of crystals constituting films and intercrystal distances are microscopically estimated with the help of optical and scanning electron microscopes. The refractive index distribution along the film thickness and the optical anisotropy of films are determined by monochromatic zero ellipsometry. The optical anisotropy of films is shown to correlate with the surface morphology.     

Surface morphology of organic thin films at various vapor flux

The surface morphology of the organic energetic material pentaerythritol tetranitrate (PETN) grown on silicon substrates has been investigated. The surface structure of the films reveal clearly differentiated morphologies which is dependent on the vapor flux. Dendrite crystals are formed with flux of 0.03 nm/s while the morphology shows a transition from dendrite branches to grain growth as the flux is increased to 0.3 nm/s. The deposition thickness did not show an obvious influence on the surface microstructure. Therefore, the deposition flux allows the production of PETN films with desired surface morphology in a controllable and reproducible way.