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Kōbe-shi, Japan

Howlader M.M.R.,McMaster University | Kagami G.,Shinko Seiki Co. | Lee S.H.,University of Texas at Dallas | Wang J.G.,University of Texas at Dallas | And 2 more authors.
Journal of Microelectromechanical Systems

To investigate the sequentially plasma-activated bonding (SPAB) mechanism of silicon/silicon wafers, the surface hydrophilicity, and the interface voids, nanostructures and chemical compositions that control the bonding quality, such as bonding strength, have been observed. Although the sequentially plasma-activated surfaces are hydrophilic, the SPAB mechanism is not identical to the hydrophilic bonding. SPAB shows high bonding strength at room temperature and water rearrangement below 150 °C, which removes the water from the interface to the bulk. This results in a thinner amorphous silicon oxide layer at the interface. Further heating of the bonded wafers desorbs water from the bulk. The heating at 225 °C starts producing hillocks at the interface, which turn into voids at temperatures above 400 °C for absorbing the hydrogen gas produced from the desorbed water at the interface. The new and bigger voids are due to the hydrogen gas at 600 °C and start accumulating at 800 °C, resulting in bubbles caused by the accumulation of voids at the preferential sites. No nitrogen exists either in silicon or in the amorphous SiO2 layer at the interface. The Si-L2,3 edges from the amorphous silicon oxide at the bonded interface are identical to those of the standard SiO2. © 2006 IEEE. Source

Tamura M.,University of Electro - Communications | Noma M.,Shinko Seiki Co. | Yamashita M.,Hyogo Prefectural Institute of Technology
Surface and Coatings Technology

Hydrogen cracking of high-strength steels is a major concern in steel processing and service, and occurs in several applications, such as cracking of rolled steel products, cold cracking of welds, and as a result of corrosion in H2S environments. Low-permeation hard coatings can be used as wear-resistant hydrogen permeation barriers. When coated on stainless steel they can reduce the rate of hydrogen transport. They might be useful for sterling engines, tritium containment, or components of hydrogen fuel cells. The hydrogen permeation behavior of BN-coated Type 316L stainless steel was investigated. In comparison with TiN and SiC coatings, the c-BN (cubic boron nitride) coating, deposited by magnetically enhanced plasma ion plating, was effective to reduce the rate of hydrogen permeation through stainless steel. The BN coating can be used for high-temperature and wear-resistant applications as hydrogen permeation barriers. © 2014 Elsevier B.V. Source

Hagihara T.,University of Hyogo | Hagihara T.,Shinko Seiki Co. | Yaori K.,University of Hyogo | Iwakura K.,University of Hyogo | And 2 more authors.
Electrochimica Acta

Abstract The electrodeposition of Pt from aqueous solutions of K2PtCl4 (Pt(II)), H2PtCl6 (Pt(IV)), and a mixture of Pt(II) and Pt(IV) was studied using the electrochemical quartz crystal microbalance (EQCM) method. Pt deposition and cathode current flow began at the same potential in the Pt(II) solution. On the other hand, in the Pt(IV) solution, the cathode current increased at a more positive potential followed by Pt deposition at a more negative potential than in the Pt(II) solution. This difference in the potentials is due to the reduction reaction of Pt(IV) to Pt(II). Thus, Pt deposition in the Pt(IV) solution occurred in two potential ranges. In the first range, which was more positive than the second one, Pt was deposited via the reduction of Pt(II) to Pt(0). In the second range, direct deposition from Pt(IV) to Pt(0) proceeded, but was followed by hydrogen adsorption, which inhibited further Pt deposition. © 2015 Elsevier Ltd. Source

Nakagami C.,Ritsumeikan University | Tonomura W.,Ritsumeikan University | Kaizuma Y.,Shinko Seiki Co. | Konishi S.,Ritsumeikan University
2013 Transducers and Eurosensors XXVII: The 17th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS and EUROSENSORS 2013

This paper presents low temperature micromachining process (below 170°C) of hydrophilic and hydrophobic materials for MEMS and μTAS. Proposed low temperature process can be applied even on poor heat resisting substrates such as paper. Paper-based μTAS employed photoresist to provide microfluidic paths and other functional patterns on paper. We reported low temperature surface treatment technology using pulse plasma CVD (hereafter PPCVD) to obtain hydrophilic/hydrophobic surface at low temperature. The SiOx/SiCx film deposited by PPCVD is used as a super hydrophilic/hydrophobic material. In this paper, we mainly demonstrated droplets patterning and microfluidic paths on paper by the hydrophilic/hydrophobic film using proposed low temperature process. © 2013 IEEE. Source

Kobayashi T.,Ritsumeikan University | Shimizu K.,Kyoto University | Kaizuma Y.,Shinko Seiki Co. | Konishi S.,Ritsumeikan University
14th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2010, MicroTAS 2010

This paper reports novel combination of hydrophilic/hydrophobic materials for the evolution of liquid manipulation. Generally, droplets can naturally be formed on hydrophilic regions, and the shape is defined by surface tension. Droplet generation based on hydrophilic/hydrophobic mechanism is a promising method for high accurate liquid manipulations [1]. However, it used to be difficult to split fluid into droplets in microchannels due to its narrow cross-section. Therefore the enhancement of wettability difference is strongly required. Our group successfully enhanced difference of contact angle from 47.5 to 94.3. Novel droplet generation and liquid transportation technologies are also described. Source

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