,
Stability to Moisture for Chemically Vapour-Deposited Boron Nitride,
Journal of Materials Science, (1989)
Аннотация
Chemically vapor-deposited boron nitride (CVD-BN) plates prepared
by the use of the boron trichloride-ammonia-hydrogen gas system were
investigated as to their stability to moisture. Infrared spectroscopic
measurement, chemical analysis and thermal gravimetric analysis were
used in this study. The synthesis conditions of CVD-BN plates have
a large influence on their stability to moisture. The stability of
CVD-BN plates prepared under a total gas pressure of 10 to 60 torr
degraded as the deposition temperature was lowered. The CVD-BN plates
with transparent and isotropic properties, which were prepared at
below 1400 C and above 10 torr, showed poor stability to moisture.
The CVD-BN plates synthesized under 5 torr had high moisture-resistance,
even at temperatures as low as 1400 C. An IR absorption spectral
study revealed that the unstable species existing in CVD-BN plates
had changed to ammonium borate hydrates by reacting with moisture
in the atmosphere. The stability to moisture for CVD-BN plates degraded
as the deposition rate was raised, especially for the CVD-BN plates
prepared at 1400 C.
