Hiroaki Toshima

Effect of dilution gases in methane on the deposition of diamond-like carbon in a microwave discharge

Abstract Diamond-like carbon was prepared by the decomposition of CH 4 in a microwave discharge. The effect of dilution gases, such as hydrogen, argon and helium, on the deposition was examined on the basis of identification of the deposits and the results of plasma diagnostics. When hydrogen was added diamond-like particles containing large amounts of hydrogen were obtained. Diamond-like films containing graphite and a smaller amount of hydrogen were deposited from the CH 4 -Ar plasma. The deposits from CH 4 and CH 4 -He plasmas consisted only of graphite. The correlation between the deposit and the species present in the plasma is discussed.

Fabrication of precision microholes and structures with smooth surfaces by a high repetition rate femtosecond laser

Precision micro holes and structures with smooth internal surfaces are introduced. We adopted a high repetition rate femtosecond laser to form optically damaged structures inside a silica glass. The glass is dissolved by HF aqueous solution after the laser irradiation. Through this process, we could obtain micro structures with smooth internal surfaces. We investigated the effects of laser repetition rate on surface roughness. It is suggested that one of the causes increased hole surface roughness is the increase in the defects by the laser irradiation.