Nobuhiko Oda

Influence of the Existence of an Underlying SiO2 Layer on the Lateral Solid‐Phase Epitaxy of Amorphous Silicon

The influence of the existence of an underlying SiO 2 layer on the lateral solid-phase epitaxy (L-SPE) of amorphous Si was investigated by comparing the characteristics of L-SPE with and without an underlying SiO 2 layer. For the L-SPE with an underlying SiO 2 layer which had a change from {110} to {111} facet growth, high density crystal defects, most of which were dislocations, were detected especially in the {111} facet growth region. The formation of {111} facets is caused primarily by high density dislocations incorporated by relaxation of the stress which originates from the retardation of Si atom rearrangement

Enhanced cycle capacity retention of plasma-sprayed SiOx nanocomposite powders for negative electrode of lithium ion batteries

Core?shell SiOx nanocomposite powders have been produced in a single continuous plasma spray process. The addition of CH4 at appropriate amounts during plasma spraying of SiO was found to be quite effective in promoting the reduction of SiO and thus increasing the crystalline Si amount after the disproportionation reaction. The half-coin cell assembled using these powders for the negative electrode has exhibited a stable capacity higher than 1000 mAh/g with the coulombic efficiency of around 99.3%, both of which are higher values than those of the cell with raw SiO. Electrochemical analysis has revealed that the resistance at the SiOx particle surface decreases potentially with Li2O formation from the beginning of the first lithiation. The decrease in the resistance is further enhanced by the addition of CH4, although more volume change is expected because of the increased crystalline Si phase content. As a result, the core?shell SiO nanocomposite produced by plasma spraying with CH4 becomes advantageous in attaining high capacity and high retention efficiency simultaneously.

A Novel Fabrication Technique of Multilayer Stacked Silicon-on-Insulator Structure Applicable to Three-Dimensional ICs

In this study, in order to investigate the feasibility of three-dimensional ICs fabricated using the combined techniques of lateral-solid phase epitaxy (L-SPE) and selective epitaxial growth (SEG) of Si, we fabricated a 5-layer stacked SOI structure and studied its characteristics. In this procedure, both epitaxy of Si for SEG on seeded windows and deposition of amorphous-Si for L-SPE were performed using ultra-low-pressure chemical vapor deposition. As a result, all single-crystalline SOI regions on each stacked layer exhibit the same graded crystallinity. We also fabricated n-channel metal oxide semiconductor field effect transistors onto the top layer. A maximum µFE of 617 cm2/(Vs) was obtained. This is the first report on the single-crystalline 5-layer stacked SOI structure.