Junichi Koike

Rolled sheets of AZ31 Mg alloys were subjected to tensile testing at temperatures ranging from room temperature to 523 K. The occurrence of grain-boundary sliding (GBS) at room temperature was demonstrated by the displacement of scribed lines across grain boundaries of deformed samples. Surface relief of deformed samples was measured by use of a scanning laser microscope. GBS strain was calculated from the measured surface step height, and its temperature dependence was analyzed by a Dorn-type c

Advancement of semiconductor devices requires the realization of an ultrathin diffusion barrier layer between Cu interconnect and insulating layers. The present work investigated the possibility of the self-forming barrier layer in Cu–Mn alloy thin films deposited directly on SiO2. After annealing at 450 °C for 30 min, a Mn containing amorphous oxide layer of 3–4 nm in thickness was formed uniformly at the interface. Residual Mn atoms were removed to form a surface oxide layer, leading to a dras

A type IIa natural diamond was irradiated at room temperature with energetic electrons. The threshold energy for displacement of atoms from their lattice sites was determined for three principal crystallographic directions by observing the formation of defect clusters during irradiation in a transmission electron microscope. The displacement-threshold energies were found to be 37.5±1.2 eV for the electron incident in the [100] direction, 45.0±1.3 eV in the [111] direction, and 47.6±1.3 eV in the

In order to understand the origin of the anomalous twinning of the {10\\bar12} type, rolled sheets of AZ31 Mg alloy were deformed at room temperature in tension along the rolling direction. An excellent correlation was found between {10\\bar12} twinning tendency and basal dislocation slip activity. Calculation of strain tensor indicated that the diagonal strain components associated with the localized basal slip can be canceled completely by the {10\\bar12} twinning. The results led to the concl

A thin diffusion barrier was self-formed by annealing at an interface between a Cu-Mn alloy film and a SiO2 substrate. The growth of the barrier layer followed a logarithmic rate law, which represents field-enhanced growth mechanism in the early stage and self-limiting growth behavior in the late stage. The barrier layer was stable at 450 °C for 100 h and at 600 °C for 10 h. The interface diffusivity was estimated from the morphology change of the barrier layer at 600 °C and was found to be smal