Sputter etching mechanism and changes of surface structure of PTFE

Growth of microscopic cones on PTFE surface by RF sputter etching process are studied. The surface texm changes from initial submicron hillocks to large cones during sputter etching. The height of these cones is 33 to 45 percent of the etching depth calculated from etching rate. The direction of these cones is nearly equal to the ion incident angle. Boundary energy of sputtering and growth of cones are 100 eV and 150 eV, respectively. It is obtained that the redeposition ratio by back diffusion to sputtered molecule is 11 percent from the experiment using collector. It is concluded that redeposition and repolymerization process of sputtered material occurs in parallel with the ion etching process, and cones continue to grow partly during etching.     

Design of A Soft X‐ray Source with Periodic Microstructure Using Resonance Transition Radiation for Tabletop Synchrotron

A soft X‐ray source with a periodic aluminum multilayer structure with vacuum layers in between for tabletop synchrotrons with low‐energy electrons was designed, and the dependence of radiation performance on structural parameters was clarified using a theoretical calculation of the resonance transition radiation. A photon density of 1 keV pr incident electron was calculated by optimizing the thickness of the aluminum and vacuum layers. Furthermore, the designed structure was fabricated by a microfabrication technique. The effects of dimensional error on the photon density are discussed on the basis of the calculated results and the prototype structure of a 6‐MeV synchrotron. It is clarified that dimensional errors of 1.5% in Al layers and of plus or minus a few dozen nanometers in the vacuum layers are negligible in obtaining a photon density of more than 90% of the maximum value. © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Photoemission study on natural oxidation of Cu3Au with synchrotron radiation

We report the results of a study of the natural oxidation of Cu₃Au(110) with high‐resolution X‐ray photoemission spectroscopy in conjunction with synchrotron radiation. The clean surface of Cu₃Au(110) is terminated with 50% Au and 50% Cu atoms. After natural oxidation in the air, Cu atoms segregate on the surface and produce Cu‐oxide. As a result, Au atoms move into the bulk. Au atoms below the oxide reduce the diffusion of O atoms farther into bulk and limit the oxide thickness. The face dependence of natural oxidation indicates that the diffusion of Cu atoms also contributes to oxide formation. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(4): 43–47, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21149     

Effect of etch gases on iridium etching using a hard mask

Abstract

The dry etching of iridium(Ir) and iridium oxide(IrO₂) using a hard mask has been studied in a high density Inductively Coupled Plasma (ICP). The etch rate and etch selectivity have been obtained in terms of gas chemistry including CI₂/O₂/Ar, HBr/O₂/Ar, and C₂F₆/O₂/Ar gases. The etch profile and the etch mechanism have been examined for various etch gases by using field emission scanning electron microscopy (FESEM) and field emission auger electron spectroscopy (FEAES). In addition, the electrical properties of the etched ferroelectric capacitors were measured for each etching gas.     

X‐ray micrographic imaging system based on COTS CMOS sensors

This paper presents the use of commercial off the shelf CMOS image sensors for the acquisition of X‐ray images with high spatial resolution. The X‐ray images, with application in biology, electronic components inspection, and paleontology research, are obtained with 8‐keV photons from a Cu tube. The quantum efficiency of the detector is estimated using attenuation lengths of photons in the sensor and compared to traditional scintillator conversion layers. The spatial resolution observed with the sensor is limited by the charge redistribution produced after photon interaction with Si.     

Synthesis and characterization of long gold nanorods

A new approach to fabricate long gold nanorods by controlling the volume of the growth solution is reported. Shapes ranging from fusiform nanoparticles to 1D rods were observed to evolve. Increasing the growth solution can control the length of the nanorods. The length of the rods could be extended to 2 µm, and nanorods with aspect ratios of up to ∼70 could be obtained. Moreover, X‐ray absorption spectroscopy (XAS) was used to elucidate the growth mechanism of gold nanorods. The gold ions were directly reduced to gold atoms by ascorbic acid during the reaction, and the gold atoms were deposited on the surface of gold seeds, which were introduced into the reaction. Extended X‐ray absorption fine structure (EXAFS) confirmed the growth of gold and the environment around Au atoms during the reaction. XAS is expected to have wide applications in the growth of gold and other related materials. © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

采用PI/PTFE复合隔膜的Li/SOCl_2电池的性能

制备了一种具有超薄、高吸液率和良好热稳定性的Li/SOCl_2电池用聚酰亚胺(PI)/聚四氟乙烯(PTFE)复合隔膜。通过SEM、同步热分析(STA)、吸液率及恒电流放电等方法,研究PI、玻璃纤维(GF)和PTFE隔膜的结构、热稳定性和吸液性能,以及复合隔膜对Li/SOCl_2电池输出电压的影响。相对于采用GF/GF隔膜的电池,采用PI/PTFE复合隔膜的电池输出电压提升了0.130 V,热生成速率降低了39.4%。     

Development of a 3‐dimensional LIGA process and application to fabricate a spiral microcoil

LIGA process has been developed in the 2.5‐dimensional world. We introduced new technologies of a 3D X‐ray lithography and a worm injection molding with an unscrewing de‐molding mechanism, and succeeded in the deployment of a 3D LIGA process. Furthermore, we fabricated a spiral microcoil using the 3D‐LIGA process and a metallization technique combining flat and smooth electroplating and isotropic chemical etching. The microcoil diameter was 0.5 mm and the length was 1 mm. The width of coil lines was 10µm and the pitch was 20µm. Characteristics of this microcoil as an inductor combine the inductance of 91 nH and the quality factor of 5.8 at the frequency of 1 GHz. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 166(1): 43–51, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20679     

Propagation and radiation field characteristics of nanometer electromagnetic waves in x‐ray dielectric waveguides with random media

X‐rays in the nanometer electromagnetic region are useful for nanospace fabrication, information and high‐energy transmission and control techniques of angstrom‐size structures in biomedical sciences and technology. In this paper, the electromagnetic fields in X‐ray gradient fiber with random refractive index media are studied. Statistical mode conversion of beam propagation, beam broadening, and beam center are investigated by the stochastic process theory of electromagnetic fields. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 139(3): 53–61, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.10002/eej.1160