Yukio Ide

Optical Emission Spectroscopy(OES) and Characterization of Hydrogenated Amorphous Carbon (a-C:H) by Ionization Deposition.

Gaseous species in the plasma during deposition influence the amount of sp2, sp3 site and hydrogen in hydrogenated amorphous carbon (a-C: H) films. Then the observation of plasma conditions were considered to be useful for a-C: H film deposition. The gaseous species were identified by optical emission spectroscopy (OES) using a spectral multichannel photodetector. And the effect of helium as an additive gas was also investigated by OES. The deposited a-C: H films were characterized by Fouriertransform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) to find the relationship with the results of OES.The identified emission spectra were Hα, Hβ and CH in plasma of methane.Emission spectra Hα, Hβ, CH and C2 were observed in the plasma of benzene and acetone, and the intensity ratio C2/α of acetone became higher than that of benzene.The decomposition of benzene was promoted owing to Penning effect of helium, as the results of OES and probe current measurement.On the other hand, Penning effect was not observed in the case of mixing methane or acetone with helium.Sharp spectra of CH, CH2sp3 bondings were found in a-C: H film deposited from methane. Spectra of CHx bonds, however, were hardly observed in a-C: H films deposited from benzene and acetone. The CH was considered to be the main precursor of a-C: H film deposition from methane. Relatively strong emission spectra of C2 appeared during deposition in plasma of benzene and acetone. It was suggested that the C2 was the main precursor in the plasma of benzene or acetone, which corresponded to finding few C-H bonding in the a-C: H films obtained from benzene and acetone as asource. It was concluded that the results of FT-IR were in accord with the results of OES.The results of XPS showed that a-C: H films deposited by ionization deposition method in the present work were extremely broad bonding and amorphous situation in comparison with diamond, graphite, polyethylene, glassy carbon and a-C: H film deposited by RF CVD.