[15a-2J-1~8] 6.4 Thin films and New materials

▲ [15a-2J-3] High-temperature H₂O beam generated by a catalytic reaction for the growth
of metal oxide thin films

Yusuke Teraguchi¹, Tomoki Nakamura¹, Kazumasa Takahashi¹, Yasuhiro Tamayama¹, Takahiro Kato¹, 〇Kanji Yasui¹ (1.Nagaoka Univ. Technol.)

Keywords:metal oxide film growth,catalytic reaction,de Laval nozzle

The high-temperature H₂O was generated in a catalytic cell and was effused through a de Laval nozzle to the reaction zone in the CVD chamber for metal oxide film growth. In this study, the temperature of the high-energy H₂O beam in the nozzle was estimated according to the theory of compressible flow for various opening angles of the de Laval nozzle, and the cluster size in the H₂O beam was also estimated. The H₂O beam temperature decreased with the opening angle, due to the difference in the cooling rates of the H₂O beam through the adiabatic expansion process. The H₂O cluster size was estimated using Hagena's empirical formula. For all H₂O nozzles, the reduced scaling parameters (Γ*) were smaller than 200 and the mean cluster sizes (<n>) were estimated to be less than 1 with an initial gas temperature and pressure of 1273 K and 1×10³-2×10⁵ Pa, respectively.