Koichi Kajiyama

Detection of Neutral Species in Silane Plasma Using Coherent Anti-Stokes Raman Spectroscopy

Coherent Anti-Stokes Raman Spectroscopy (CARS) has been employed for the first time to investigate silane (SiH4) glow-discharge plasma. By measuring ν1 vibrational line of silane as a function of position between the two electrodes, spatial distribution of silane (number density) in the (bulk) plasma has been determined for various gas pressures. It has been demonstrated that CARS is an excellent diagnostic tool for a chemically-active plasma such as silane-based glow discharge.

Crystallization of long polycrystalline silicon with a long duration pulse from a Nd:YAG laser system

We have investigated the crystallization of a long polycrystalline silicon (poly-Si) annealed by a single-shot laser pulse, which is generated from a novel variable-pulse-duration laser system. We report a quantitative study of the correlation between the crystal length and the laser pulse parameters (in particular, pulse energy per unit area and duration). The laser system consists of two laser sources: a constant short-duration pulsed laser (? = 532 nm, duration = 20 ns) and a variable-duration pulsed laser (? = 1064 nm, duration = 80?1300 ns). The two pulses, which were generated from separate laser sources, were incident on the substrate at almost the same time. By using the laser system, it is experimentally found that there is a proportional relationship between the crystal length and the pulse energy per unit area of the 1064 nm pulse, and we obtained poly-Si crystals with an average length of more than 10 ?m by increasing the pulse energy per unit area of the 1064 nm pulse and expanding the pulse duration. To interpret the experimental results, we have also qualitatively considered the crystallization of a long poly-Si.

Visualizing study on swirling flow induced into cylinder of motored model engine.

To make clear the behavior of swirling flow induced into cylinder of a motored model engine with high swirl port, the pattern and direction of air flow in the cylinder are visualized at every crank angle during intake process by using a spark tracing and particle tracing techniques, changing the position of spark electrode.Consequently, several characteristics of air flow induced into cylfinder, such as the direction, induced angle and center of swirlingflow, are determined at every crank angle and several cross-sectionsof cylinder.