TITLE:
Recovery Method of Pyrolytic Carbon Surface after Exposure to Chlorine Trifluoride Gas
AUTHORS:
Masaya Hayashi, Keisuke Kurashima, Hitoshi Habuka, Akio Ishiguro, Shigeaki Ishii, Yoshiaki Daigo, Hideki Ito, Ichiro Mizushima, Yoshinao Takahashi
KEYWORDS:
Pyrolytic Carbon, Recovery, Chlorine Trifluoride, Fluorine Out-Diffusion, Annealing
JOURNAL NAME:
Advances in Chemical Engineering and Science,
Vol.11 No.1,
January
15,
2021
ABSTRACT: An annealing process was developed for the practical
recover of a purified py-rolytic carbon (PPyC) surface from damage, such as
color change and peeling, due to fluorination during exposure to chlorine
trifluoride gas at high tempera-tures for the cleaning of a silicon carbide
chemical vapor deposition reactor. The PPyC surface was annealed at 900°C for
10 min in ambient nitrogen con-taining oxygen at the concentrations of 0.01% -
20%. The rainbow-like colored surface returned to the dark gray color of the
original PPyC. Simultaneously, the thin peeled films disappeared. The Raman
spectra showed that the PPyC surface chemical bonding returned to that of the
original one. The oxygen concentration as low as 0.01% could recover the PPyC
surface along with re-ducing the surface pit formation, when the combination of
the exposure to chlorine trifluoride gas and the recovery was repeated.