Disilane (Si2H6) was photodissociated with an ArF excimer laser and the radicals produced were probed by resonantly enhanced multiphoton ionization spectroscopy (REMPI) and laser-induced fluorescence spectroscopy (LIF). Silicon and hydrogen atoms, and SiH and Si2 molecules were detected. It was found that temporal changes of the densities of Si and Si2 were controlled by diffusion in the present experiment. Absolute density calibration of the measured REMPI signals is also presented.

Plasma-enhanced photoemission spectroscopy has been applied to in situ monitoring of thin-film formation during CH4/Ar rf plasma chemical vapor deposition (CVD). The behavior of the photoemission signal during CVD is described, along with basic characteristics of photoelectric signals in H2 rf plasma.

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Design and performance details of a 5-kW cw arc-lamp-pumped Nd:YAG laser are given. Two types of 5-kW Nd:YAG lasers have been developed, which have enough laser power and beam intensity necessary to realize deep penetration and high speed welding of metals. Experiments of welding and thick plate cutting were performed in order to investigate the ability of 5-kW Nd:YAG lasers. Maximum penetration of 15mm is achieved with stainless steel and that of 6mm with aluminum alloys. Moreover high speed welding up to 8m/min is realized.

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