Application of X-ray scattering technique to the study of supersmooth surfaces

Applications of the X-ray scattering technique for studying supersmooth surfaces with rms roughness of 0.1–0.2 nm are discussed. The experimental schemes are analyzed and systematic errors on the determination of 2D and 1D PSD-functions are evaluated. Results of laboratory and synchrotron experiments are presented on the study of roughness of superpolished substrates made of different materials as well as for B₄C films of different thickness.     

非接触型光外差轮廓仪

本文介绍一种纳米级非接触型高精度光外差轮廓仪,它是基于普通光路的光外差干涉仪。工件表面被两束有微小频差的激光束所照射,其中一束经聚焦后用作测量光探针来扫描工件表面,另一束则用作参考光束。两束光经表面反射后产生干涉。测量信号和参考信号的相位差与表面的微不平值成正比。仪器的横向分辨率为2μm,高度分辨率为1 nm,它不需要对试样作大范围的调整,且可用试样自身作参考面。信号经光电转换后由微型计算机进行处理,它能快速完成测量、计算、显示及打印出各种参数和曲线。     

Grain refinement in electrogalvanized coatings

The effects of grain-refining additives on the morphology and surface roughness of zinc deposits plated at 80 A/dm² is presented. Atomic force microscopy (AFM) images show zinc deposits plated without additives are rough and are not of commercial quality. The addition of a suppressor compound and a grain refiner reduces the grain size and surface roughness. Increased concentration of the grain refiner results in a further reduction of the surface roughness, the width and height of the zinc grains. AFM is a convenient way to monitor the changes in zinc morphology with additive concentrations.     

表面粗糙度评定的小波基准线

给出了一条新的粗糙度评定基准线———小波基准线。此线是曲面轮廓线、形位误差及波纹度等低频信号的综合。与传统的评定基准线相比,其优点是：光滑自然,没有特定的函数形式;由数据的小波分解产生,精度高。     

Surface characteristics of water-repellent polyelectrolyte multilayer films containing various silica contents

Water-repellent films were dip-coated onto glass substrate by mimicking a unique surface feature of the lotus leaf by a layer-by-layer deposition of polyelectrolyte, followed by SiO₂ particle to modify surface roughness, and finally a semifluorinated silane to lower the surface energy. Two types of the SiO₂, a fine-sized Aerosil^® 200 and a coarse-sized Aeroperl^® 300/30, were employed at various contents to modify the films' surface roughness. SEM and AFM analysis revealed that the Aerosil^® 200 had more uniform deposition onto the etched polyelectrolyte layer due to its very fined size while the Aeroperl^® 300/30 had less uniform deposition due to its coarser size. In both cases, higher SiO₂ content in the films led to more surface roughness and more hydrophobicity, although the effect was not dramatic in the case of Aerosil^® 200. The films containing the Aerosil^® 200 had very high contact angles of 167-175°and very low surface energy of 0.03-0.51 mJ m^− 2, while the films containing the Aeroperl^® 300/30 had lower contact angles of 132-154°and higher surface energy of 3.07-11.29 mJ m^− 2.     

Effect of Cu surface segregation on properties of NiFe/FeMn bilayers

The films of NiFe/FeMn with Ta and Ta/Cu buffer layers were prepared by magnetron sputtering. Results show that the exchange bias field of NiFe/FeMn films with Ta/Cu buffer is lower than that of the films with Ta buffer. The crystalline texture, surface roughness and element distribution of these two sets of samples were examined, and there is no apparent difference for the texture and roughness. However, the segregation of Cu atoms on the surface of NiFe in the trilayer of Ta/Cu/NiFe has been observed by using the angle-resolved X-ray photoelectron spectroscopy. The decrease of the exchange bias field for NiFe/FeMn films with Ta/Cu buffer layers is mainly caused by the diffusion of Cu atoms through NiFe layer, which stayed at the interface of NiFe/FeMn film or even intruded into FeMn layer. The present results indicate that Cu segregation through NiFe layer should be suppressed in order to improve the exchange bias field in giant magnetoresistance spin valves with Cu spacer.     

取样长度和采样点数对分维值的影响

在研究分形几何理论的基础上,以不同的取样长度和采样点数,对大量的机加工粗糙表面进行了测量。结果表明;传统的粗糙度评定参数Ｒα依赖于取样长度;而分形维数Ｄ则是表征表面的固有参数,与取样长度无关,虽然受采样点数的影响,但当采样点数足够多时,Ｄ值将趋于稳定。     

气体离化团束对表面的平坦化及清洁化效果

用原子力显微镜测量了气体离化团束照射后表面粗糙度的变化。已经证实气体团束轰击对表面沾污具有很高的清除率，同时却引起较低的损伤。气体离化团束优良的平坦化和清洁化效果可能与照射中多体碰撞、侧向溅射及高能量密度的沉积相关。     

表面粗糙度参数的计算方法

介绍了表面粗糙度参数的计算方法,并用ＱｕｉｃｋＢＡＳＩＣ语文编程实现。     

Random phase mask as a model of a rough surface: Part II. Experiment

Artificial roughness was created on sample surfaces by etching through a two-dimensional orthogonal grating with a stochastic distribution of square "defects" of size. "Defects" depth was varied from 0.02 μm up to 1.005 μm. The experimental dependences of the scattering of polarized light were studied on four types of surface roughness for two materials: quartz and aluminum. The defect sizes of the random phase mask were 25 × 25 μm and 2.5 × 2.5 μm. The impacts of the sizes and density of artificial defects of rough surfaces on the polarization of reflected light were investigated by multiple-angle-of-incidence (MAI) ellipsometry at a wavelength of 0.63 μm.     

Influence of Ar plasma treatment on the wetting behavior of pharmaceutical powders

In this study, corn starch and ibuprofen are treated in Argon (Ar) plasma to enhance the wettability of the powders without using any additive or guest particle. The powder and pellets were exposed to the Ar plasma for different time intervals (5–20?min) at optimized pressure and voltage. While the morphological changes due to plasma exposure are captured by SEM, the AFM measurement shows the variations in surface roughness for both corn starch and ibuprofen powders. The XPS and surface energy results confirm that the surface groups change is dominating under initial exposure, but longer exposure creates more damaging effect than building the new active sites at the surface. The contact angle (CA) measurement shows that with increase in treatment time, the CA decrease from 48° to 33° for corn starch and 69° to 51° for ibuprofen. A comparison of experimentally obtained CA and that of theoretically calculated CA shows that there exists some difference. This may be attributed to the absence of surface group contribution in the Wenzel model. The present study shows that short exposure is sufficient enough to improve the wetting where the surface group plays a dominant role over surface roughness.     

表面粗糙度的光学测量方法

表面粗糙度的光学测量方法,具有非接触、精度高和响应快等优点,致使研究十分引人注目,发展极快。本文简单介绍了几种典型的光学测量原理和方法及一些商品化的仪器。     

Characteristics of aluminum-implanted 6H-SiC samples after different thermal treatments

Multiple energy aluminum (Al) implantations were performed at room temperature in n-type epitaxial 6H-SiC layers, aiming at amorphizing the material from the surface up to a depth inferior to 0.5 μm. Annealings were then carried out in an induction furnace. The goal of this paper is to optimize the furnace geometrical configuration, in order to reduce the surface degradation and improve the crystal reordering. This optimization was established for one-side amorphized wafers, which need restricting annealing parameters, and is therefore supposed to be valid for less crystal damaging implantations. Two types of geometrical parameters were essentially studied: the internal configuration, which tends to increase the silicon partial pressure inside the reactor, and the position of the sample, which has a direct influence on the recrystallization and on the dopant electrical activation. The annealings are compared for the same thermal parameters: the plateau temperature (1700 °C), the annealing duration (30 min), and the heating rate (60 °C s⁻¹). The surface roughness was evaluated by using atomic force microscopy. Two final configurations were retained, leading to satisfactory results with respect to the as-implanted material: (i) Rutherford backscattering spectrometry in channeling geometry revealed a very good recrystallization in both cases, giving a signal level similar to the virgin crystal one; (ii) secondary ion mass spectrometry showed two distinct results depending on the sample position: one position led to some material etching, especially the SiC part which was amorphized by the implantation, and the second position gave rise to the deposition of a crudely monocrystalline SiC layer on the surface of the sample implanted side. This coating was found to prevent from any dopant loss by exodiffusion or material etching. Electrical measurements (four-point probe at 300 K) proved an Al substitutional ratio of 97 and 78% depending on the configuration, giving room temperature sheet resistances of about 2×10⁴ and 4×10⁴ Ω sq.⁻¹, respectively, for 4×10¹⁹ cm⁻³ Al implanted samples.     

Determination of the relative surface areas of PVD coatings by electrochemical impedance spectroscopy

The application of electrochemical methods for the determination of the real surface area of PVD coatings is explored. Titanium and chromium coatings with different growth morphologies and surface topographies were fabricated by magnetron sputtering. The morphology was characterized by SEM and its effect on the electrochemical polarization behavior of the coatings was studied by linear sweep voltammetry in 5 M HCl and 0.66 M NaCl. The nominal current densities measured were consistently higher for coatings having a coarse microstructure. Impedance spectroscopy was used to determine the real surface area of the films relative to a flat surface produced by mechanical polishing. When corrected for the real surface area, the polarization current density at a given potential did not depend on film morphology, both for titanium and chromium. The present paper demonstrates that electrochemical impedance spectroscopy is a useful method for the estimation of the surface area of PVD coatings.     

精密U薄膜的制备及表征

采用机械磨抛、表面轮廓仪以及AES分析等方法，制备并表征了精密U薄膜。结果表明，获得了厚度从约50μm深减薄到约10μm厚的U薄膜，该薄膜的表面粗糙度Ra、Rq均低于50nm，但峰谷极差Tir大于100nm。薄膜越薄，Ra，Rq，Tir和厚度不一致性均有所增大，且薄膜的厚度一致性随着取样长度的增加有所减小。对实验结果进行了讨论。     

A chemical mechanical polishing model incorporating both the chemical and mechanical effects

A comprehensive model for the material removal in a chemical mechanical polishing (CMP) process is presented in which both chemical and mechanical effects are taken into consideration. The chemical effects come into play through the formation of chemically modified surface layer on the wafer surface that, in turn, is removed mechanically by the plastic deformation induced by slurry particles. This model describes the influence of most, if not all, variables involved in the CMP process including slurry characteristics (solid loading, particle size and distribution, modulus), pad properties (modulus, hardness, asperity sizes and distribution) and processing conditions (down-pressure, velocity). Although more elaborate experimental verification of the model is yet to follow, this model appears to be capable of explaining many experimental observations on both oxide and metal CMP that, otherwise, could not be explained properly.