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[Author] Hiroki OGAWA(4hit)

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  • Chemical Structures of Native Oxides Formed during Wet Chemical Treatments of Silicon Surfaces

    Hiroki OGAWA  Takeo HATTORI  

     
    PAPER

      Vol:
    E75-C No:7
      Page(s):
    774-780

    Chemical structures of native oxides formed during wet chemical treatments of silicon surfaces were investigated using X-ray Photoelectron Spectroscopy (XPS) and Fourier Transformed Infrared. Attenuated Total Reflection (FT-IR-ATR). It was found that the amounts of Si-H bonds in native oxide and at native oxide/ silicon interface are negligibly small in the case of native oxides formed in H2SO4-H2O2 solution. Based on this discovery, it was found that native oxides can be characterized by the amount of Si-H bonds in the native oxide and the combination of various wet chemical treatments with the treatment in NH4OH-H2O2-H2O solution results in the drastic decrease in the amount of Si-H bonds in the native oxides.

  • Initial Stage of SiO2/Si Interface Formation on Si(111) Surface

    Hiroshi NOHIRA  Yoshinari TAMURA  Hiroki OGAWA  Takeo HATTORI  

     
    PAPER

      Vol:
    E75-C No:7
      Page(s):
    757-763

    The initial stages of SiO2/Si interface formation on a Si(111) surface were investigated at 300 in dry oxygen with a pressure of 133 Pa. It was found that the SiO2/Si interfacial transition layer is formed in three steps characterized by three different oxidation rates.

  • Study on Elemental Technologies for Creation of Healthcare Chip Fabricated on Polyethylene Terephthalate Plate

    Akio OKI  Yuzuru TAKAMURA  Takayuki FUKASAWA  Hiroki OGAWA  Yoshitaka ITO  Takanori ICHIKI  Yasuhiro HORIIKE  

     
    PAPER

      Vol:
    E84-C No:12
      Page(s):
    1801-1806

    Elemental technologies have been studied to establish the healthcare chip which is an intelligent micro analytical system to detect human health markers from a trail of blood. A two steps process for deep quartz dry-etching was discussed in order to overcome the issues of concave-shaped defects at the bottom of grooves. A coating with 2-methacryloyloxyethylphosphorylcholine (MPC) polymer was studied to suppress the adsorption of bio-substance onto the inner wall of the flow channel on chip and good bio-compatibility was achieved for suppression of protein adsorption and blood cell adhesion. A prototype of healthcare chip was fabricated on polyethylene terephthalate (PET) plate using a micro molding technique. Using this chip, the ion concentrations of pH, Na+, K+, Ca++ were successfully measured with embedded ion sensitive field effect transistors (ISFET's).

  • Media Synchronization Quality of Reactive Control Schemes

    Yutaka ISHIBASHI  Shuji TASAKA  Hiroki OGAWA  

     
    PAPER-Multimedia Systems

      Vol:
    E86-B No:10
      Page(s):
    3103-3113

    This paper assesses the media synchronization quality of recovery control schemes from asynchrony, which are referred to as reactive control schemes here, in terms of objective and subjective measures. We deal with four reactive control techniques: skipping, discarding, shortening and extension of output duration, and virtual-time contraction and expansion. We have carried out subjective and objective assessment of the media synchronization quality of nine schemes which consist of combinations of the four techniques. The paper makes a comparison of media synchronization quality among the schemes. It also clarifies the relations between the two kinds of quality measures.