Spectral-Directional Emittance of 99.99% Aluminum, Thermally Oxidized Below Its Melting Point

Spectral-directional emittance measurements for 99.99% aluminum, thermally oxidized in air, were performed using a radiometric technique. The apparatus is comprised of a Fourier transform infrared spectrometer and a blackbody-radiating cavity. The sample holder is held on a slotted arc rack, which allows directional measurements from normal to grazing angles. The aluminum sample was heated for an extended period of time (150 h) at high temperature below its melting point prior to performing measurements. The data presented here cover the spectral range between 3 and 14 μm, directional range from surface normal to 72° polar angle, and temperatures from 673 to 873 K. The complex index of refraction is also reduced from emittance data. Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS), and Auger depth profiling were used as surface techniques to characterize the thickness and composition of aluminum oxide film that formed on the metallic surface.     

Reference-free total reflection X-ray fluorescence analysis of semiconductor surfaces with synchrotron radiation

Total reflection X-ray fluorescence (TXRF) analysis is a well-established method to monitor lowest level contamination on semiconductor surfaces. Even light elements on a wafer surface can be excited effectively when using high-flux synchrotron radiation in the soft X-ray range. To meet current industrial requirements in nondestructive semiconductor analysis, the Physikalisch-Technische Bundesanstalt (PTB) operates dedicated instrumentation for analyzing light element contamination on wafer pieces as well as on 200- and 300-mm silicon wafer surfaces. This instrumentation is also suited for grazing incidence X-ray fluorescence analysis and conventional energy-dispersive X-ray fluorescence analysis of buried and surface nanolayered structures, respectively. The most prominent features are a high-vacuum load-lock combined with an equipment front end module and a UHV irradiation chamber with an electrostatic chuck mounted on an eight-axis manipulator. Here, the entire surface of a 200- or a 300-mm wafer can be scanned by monochromatized radiation provided by the plane grating monochromator beamline for undulator radiation in the PTB laboratory at the electron storage ring BESSY II. This beamline provides high spectral purity and high photon flux in the range of 0.078-1.86 keV. In addition, absolutely calibrated photodiodes and Si(Li) detectors are used to monitor the exciting radiant power respectively the fluorescence radiation. Furthermore, the footprint of the excitation radiation at the wafer surface is well-known due to beam profile recordings by a CCD during special operation conditions at BESSY II that allow for drastically reduced electron beam currents. Thus, all the requirements of completely reference-free quantitation of TXRF analysis are fulfilled and are to be presented in the present work. The perspectives to arrange for reference-free quantitation using X-ray tube-based, table-top TXRF analysis are also addressed.     

Electrostatically actuated resonant microcantilever beam in CMOS technology for the detection of chemical weapons

The design, fabrication, and testing of a resonant cantilever beam in complementary metal-oxide semiconductor (CMOS) technology is presented in this paper. The resonant cantilever beam is a gas-sensing device capable of monitoring hazardous vapors and gases at trace concentrations. The new design of the cantilever beam described here includes interdigitated fingers for electrostatic actuation and a piezoresistive Wheatstone bridge design to read out the deflection signal. The reference resistors of the Wheatstone bridge are fabricated on auxiliary beams that are immediately adjacent to the actuated device. The whole device is fabricated using a 0.6-/spl mu/m, three-metal, double-poly CMOS process, combined with subsequent micromachining steps. A custom polymer layer is applied to the surface of the microcantilever beam to enhance its sorptivity to a chemical nerve agent. Exposing the sensor with the nerve agent simulant dimethylmethylphosphonate (DMMP), provided a demonstrated detection at a concentration of 20 ppb or 0.1 mg/m/sup 3/. These initial promising results were attained with a relatively simple design, fabricated in standard CMOS, which could offer an inexpensive option for mass production of a miniature chemical detector, which contains on chip electronics integrated to the cantilever beam.     

Determination of crystallization as a function of Mo layer thickness in Mo/Si multilayers

Mo/Si multilayer samples with different Mo layer thickness were deposited by electron beam evaporation, while Kr⁺ ions (300 eV) were used for polishing the Si layers. Crystallization as a function of the Mo layer thickness deposited was investigated by grazing incidence X-ray diffraction, giving information on the crystalline phases, average size and crystallite formation. Comparison of these parameters for the samples examined provided novel results, especially regarding the in-plane and in-depth average sizes of the crystallites. The most important result is that crystallization takes place already when a 1 nm thick Mo layer has been deposited. Moreover, the average in-plane size of the crystallites was found to be independent of the layer thickness, while the average in-depth size corresponded to the thickness of the Mo layer. Depositions consist of polished Si layers were found to give a larger amount of crystalline material compared to those consist of unpolished Si layers.     

Gap and Mie plasmons in individual silver nanospheres near a silver surface

We study the plasmons confined at the gap between silver nanospheres and silver planar surfaces by means of angle- and space-resolved spectral cathodoluminescence. Plasmons in individual nanoparticles are excited by an electron beam, giving rise to light emission that is analyzed as a function of photon-energy, emission direction, and position of the beam spot. Gap plasmons are significantly red shifted due to the interaction between the particles and the metal substrate, and they are preferentially excited by positioning the beam close to the sphere centers, which results in an angular emission pattern similar to that of a dipole oriented along the surface normal. In contrast, weaker emission features are observed at higher-energies when the beam is grazing to the spheres, corresponding to the excitation of Mie plasmons like those of isolated particles, which display an angular pattern approximately mimicking a dipole parallel to the surface. Our measurements are in excellent agreement with simulations, thus providing useful insight into gap plasmons arising from the interaction between metal particles and metal substrates that are relevant for molecular sensing applications.     

连续电子束扫描处理的U-5.5Nb合金的表面层微结构和性能

采用连续电子束扫描处理技术(CEBSP)首次在U-5.5Nb合金表面制备了重熔改性层,通过OM、SEM/EDS、便携式表面粗糙度测量仪及维氏硬度计等分析方法对重熔改性层的微观结构与物性特征进行了表征、分析。研究结果表明:由于快速熔凝会形成含有大量细小夹杂且具有枝晶组织的重熔改性层(厚度为毫米级),使其表面微观硬度从基体的164.5HV0.3升高至重熔改性层的211.5HV0.3。利用Kou模型计算了重熔改性层在快速凝固过程中裂纹敏感性因子-固相分数关系曲线,分析认为凝固裂纹是高Nb含量U-Nb合金在快速熔凝过程中难以避免的一类表面缺陷,也是表面粗糙度Ra从初始相对光滑表面0.193μm升高至重熔改性层表面2.298μm的主要原因。     

Low-temperature nitriding of titanium in low-energy electron beam excited plasma

The effect of an electron beam and the related plasma on the structure, phase state, and microhardness of the surface of titanium has been studied in a broad range of beam currents (0.1–2.5 A), electron energies (0.1–1 keV), and gas pressures (0.01–1 Pa). This range was ensured by the grid stabilization of emissive properties of the plasma electron source, which formed a wide (∼40 cm²) electron beam in a space charge layer between the beam-excited plasma and the grid bounding the plasma cathode. The sample temperature (350–900°C) was determined by the electron beam parameters. The plasma density was additionally controlled by changing the gas (N₂ or Ar-N₂ mixture) pressure. It is established that, during the low-temperature nitriding process in low-energy electron beam plasma, the ion sputtering significantly affects the microhardness of a processed surface and the rate of growth of the hardened layer thickness. The possibility of nitriding at a low (−50 V) or floating potential of the sample eliminates the development of a surface relief and allows the process to be carried out in deep and narrow slits.     

Miniature and MEMS-type vacuum sensors and pumps

In the paper, the observable trends of the actual research and development of selected types of miniature and MEMS-type vacuum sensors are presented. Some information about the new types of active vacuum gauges, which are offered by the leading manufacturers of the vacuum measurement instruments, is given. Next, the list of MEMS devices that need vacuum for proper operation is presented. Some aspects of vacuum-encapsulation of MEMS devices, on wafer level and package level are shown. The new conceptions of obtaining and maintenance of high and ultra-high vacuum in MEMS devices are described. They concern the conception of integration of a miniature orbitron pump on-chip with MEMS-type device or with vacuum part of the portable advanced instruments such as electron microscope, ion mass spectrometer, and free electron laser.     

307 200 pixels/cm resolution phosphor screen in monochrome CRT

We have studied the screen luminance versus irradiation densities of electron beam on phosphor screens, by using the monochrome miniature CRTs. It is found that for irradiation of electron beam on phosphor screens, there is a critical condition which is determined by the electric field of the holes (∑E_h) in the surface volume of the phosphor particles. The clear, sharp, and flickerless images at a high luminance are obtained in the region of ∑E_h<E_a in which the screen luminance has a linear relation with the electron beam densities, where E_a is the electric field at top layer of screen by the anode. In the region of ∑E_h>E_a, the cathodoluminescence images smear, flicker, and fade due to the surface-bound-electrons on phosphor particles. A high resolution image (307 200 pixels/cm²) of VGA (640×480 pixels/cm²) at 2000 cd/m² is obtained with the screen of a practical 0.5 in. CRT(1 cm²), which is operated with the region of ∑E_h<E_a.     

Deformation of Mesoporous Titania Nanostructures in Contact with D2O Vapor

For many applications, mesoporous titania nanostructures are exposed to water or need to be backfilled via infiltration with an aqueous solution, which can cause deformations of the nanostructure by capillary forces. In this work, the degree of deformation caused by water infiltration in two types of mesoporous, nanostructured titania films exposed to water vapor is compared. The different types of nanostructured titania films are prepared via a polymer template assisted sol–gel synthesis in conjunction with a polymer‐template removal at high‐temperatures under ambient conditions versus nitrogen atmosphere. Information about surface and inner morphology is extracted by scanning electron microscopy and grazing incidence small‐angle neutron scattering (GISANS) measurements, respectively. Furthermore, complementary information on thin film composition and porosity are probed via X‐ray reflectivity. The backfilling induced deformation of near surface structures and structures inside the mesoporous titania films is determined by GISANS before and after D₂O infiltration. The respective atmosphere used for template removal influences the details of the titania nanostructure and strongly impacts the degree of water induced deformation. Drying of the films shows reversibility of the deformation.     

A compact CMA spectrometer with axially integrated hybrid electron-ion gun for ISS,AES and sputter depth profile analysis

Until now, the combined application of electrons and ions in surface analysis required two separate sources for electrons and ions with different incidence angles. The newly developed hybrid electron-ion gun, however, allows bombardment of the same sample area both with noble gas ions and with electrons coming from the same direction. By integrating such a hybrid gun axially in a cylindrical mirror energy analyser (CMA) a sensitive compact single flange spectrometer obtains for ion scattering spectroscopy (ISS), Auger electron spectroscopy (AES), and sputtering all within normal beam incidence. This concept makes accurate beam centring very easy. Additionally, the bombardment from the same direction both for sputtering and for surface analysis brings advantages in depth profiling. The scattering angle for ISS has a constant value of about 138°. The hybrid gun delivers typically an electron beam current of −20 μA at 3 keV for AES, and an ion beam current of +40 nA and +1.2 μA at 2 keV for ISS and sputtering respectively. The switching time between ISS, AES, and sputtering mode is about 0.1 s. So this system is best suited for automatically controlled depth profile analysis. The design and operation of this new system will be described and some applications will be discussed.     

渗氮与Ni－Cu－P刷镀复合处理表面的摩擦学性能

利用球－盘摩擦磨损试验机研究了边界润滑条件下４５＃钢渗氮表面刷镀Ｎｉ－Ｃｕ－Ｐ镀层的摩擦学性能．结果表明,在硬度较高且具热硬性的渗氮层上刷镀较软的Ｎｉ－Ｃｕ－Ｐ镀层,可较４５＃钢直接刷镀Ｎｉ－Ｃｕ－Ｐ镀层及未刷镀的渗氮层,摩擦学性能全面显著提高．还利用扫描电子显微镜和铁谱仪对磨损表面的成分、形貌和磨屑形态进行了分析．     

On the electron microprobe analysis of structured magnetic thin films

The electron microprobe analysis of sputtered FeSi and sputtered or electroplated NiFe films with different structures is reported. The layer thicknesses are between 5 × 10² and 10⁴ Å. The sources of error of a wavelength dispersive spectrometer are compared with those of an energy dispersive spectrometer. Both have been tested by variation of the spectrometer geometry, the inclination of the thin film plane, and the chemical composition, surface roughness and thickness of the films. The calibration was made by X-ray fluorescence and atomic absorption analysis.     

Electromagnetic scattering by refractive index variations over a rough conducting surface

Abstract

This paper presents a numerical method for calculating the scattered field when a vertically polarized Gaussian beam is incident on a flat or slightly rough conducting surface at a grazing angle and the refractive index of the propagation medium has a profile which is not constant. The method is a solution to the parabolic approximation of the full wave equation. The results presented are taken for a linear and log-linear refractive index profile.     

Absolute calibration in grazing incidence interferometry via rotational averaging

Interferometry in grazing incidence can be used to test cylindrical mantle surfaces. The absolute accuracy of the resulting surface profiles is limited by systematic wavefront aberrations caused in the interferometer, in particular due to an inversion of the test wavefront in an interferometer using diffractive beam splitters. For cylindrical specimens, a calibration method using four positions has therefore been investigated. This test is combined with another method of optical metrology: the rotational averaging procedure. The implementation for grazing incidence is described and measurement results for hollow cylinders are presented. The gain in accuracy is demonstrated.     

Observation and analysis of self-organized surface grain structures in silica films under nonepitaxial growth mode

Silica films under present reactive electron beam deposition conditions have depicted a novel self-organized surface grain structures when probed through atomic force microscopy, 2D fast Fourier transform and glancing incidence X-ray diffraction techniques. The formation of such ordered surface grain structures is observed to be strongly correlated to the nucleation and growth process of the silica films. However, the nature of the substrate (amorphous or crystalline) and multilayer geometries have influenced the shapes, sizes and abundances in the grain structures and the ordering. The strain mediation of such ordered structures when buried under polycrystalline layers like Gd₂O₃ have shown to influence both the grain size as well as roughness. A variety of grain structure evolutions and morphological changes in silica layers were noticed in different multilayer geometries. It is, hence, inferred that by appropriately using combinations of these materials, it is possible to have a control over the multilayer morphology and grain structures, which is a very relevant factor in developing precision ultraviolet laser coatings.     

Energy-dispersive X-ray-absorption edge spectrometry with spectrum filtration by X-ray mirrors

A highly sensitive energy-dispersive scheme with a semiconductor spectrometer is proposed for determining impurity concentrations from the X-ray-absorption edge spectra. The optimization of spectrum in a band studied is ensured by sequential reflections of transmitted radiation from X-ray mirrors and by variation of the grazing angle of the analyzed beam. Results of measurements of the X-ray-absorption edge spectra of Fe in dispersed salt samples and W impurity in beryllium plate are presented. It is shown that the problem of deconvolution can be numerically solved by smoothing X-ray-absorption fine-structure oscillations with power functions.     

Modeling liquid-crystal devices with the three-dimensional full-vector beam propagation method

Simulation of light propagation within nematic liquid-crystal (LC) devices is considered, of which the director is aligned normal to the z axis. A three-dimensional full-vector finite-difference beam propagation method for an anisotropic medium is presented and an alternating direction implicit scheme is adopted. Simulations of light propagation in a bulk polarization converter, a waveguide with a LC covering layer, and an integrated polarization splitter and optical switch are presented. Comparison with an existing simulation method is carried out for beam behavior within the bulk polarization converter. The effect of strong surface anchoring of a LC cell on the beam behaviors within the integrated switch is also demonstrated.     

Microstructure of tool steel after low temperature ion nitriding

Abstract

The microstructural development in H13 tool steel upon nitriding by an ion beam process was investigated. The nitriding experiments were performed at a relatively low temperature of ～400°C and at constant ion beam energy (400 eV) of different doses in a high vacuum preparation chamber; the ion source was fed with high purity nitrogen gas. The specimens were characterised by X-ray photoelectron spectroscopy, electron probe microanalysis, scanning and transmission electron microscopy, and grazing incidence and Bragg–Brentano X-ray diffractometry. In particular, the influence of the nitrogen surface concentration on the development of the nitrogen concentration depth profile and the possible precipitation of alloying element nitrides were discussed.     

Ion beam effects on dust grains: 2—Influence of charging history

Dust grains in space are charged by various processes. Impacts of energetic ions lead to deposition of positive charge on the grain, increasing the grain potential and, as a consequence, the electric field at its surface. The accumulated charge is spontaneously released as an emission current when the electric field reaches a threshold. This discharging current is usually attributed to field ionization of any gas surrounding the grain or to ion field emission and would thus be predominantly a function of the surface potential. However, preliminary studies [Velyhan A, Z?ilavý P, Pavl? J, S?afránková J, Něme?ek Z. Ion beam effects on dust grains. Vacuum 2004;76:447-55] using melamine formaldehyde spheres have shown that the discharging current depends strongly on the energy of primary ions. The present paper continues these investigations with the motivation to understand the whole charging/discharging process. The experiment is based on the capture of a single dust grain in an electrodynamic quadrupole. The trapped grain is exposed to an ion beam with different energies up to 5 keV and its charge and surface potential are estimated from the frequency of its oscillations in the quadrupole. The charging/discharging currents are determined from temporal changes of the grain charge. Our results suggest that the grain charge is accumulated in a thick surface layer of non-conducting samples. The thickness of this layer depends on the mass and energy of primary ions. On the other hand, the beam ions probably recombine on the metallic surfaces and create an adsorbed layer there. We believe that the main discharging process is field desorption complemented in this particular case with post-ionization.