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42 results on '"Akiyama, Yasunobu"'

8. Silicon Dioxide Film Deposition by Afterglow-Plasma-Enhanced Chemical Vapor Deposition using Triethoxysilane and Tetraethoxysilane

Author

Shin, Youngsik, Akiyama, Yasunobu, Imaishi, Nobuyuki, and Jung, Sangchul

Subjects
Tetrathoxysilane, Triethoxysilane, CVD, SiO_r Afterglow plasma
Abstract

Silicon dioxide (SiO2) films were deposited by afterglow-plasma-enhanced CVD using triethoxysilane (TRIES) and tetraethoxysilane (TEOS) as source materials. TRIES has approximately four times higher vapor pressure than TEOS. The growth rate using TRIES was approximately twice as high as that using TEOS under the same operating conditions. The step coverage of film grown by TRIES was better than that by TEOS under a wide range of operating conditions. These results suggest that TRIES is a good candidate for SiO2 films.

Published
2003

9. Gas-Phase Reaction Rate During ZrO2 Thin-Film Formation by LPMOCVD. Comparison of growth rate distributions obtained theoretically and experimentally

Author

Akiyama Yasunobu, Nakano Katsuyuki, Sato Tsuneyuki, and Imaishi Nobuyuki

Subjects
Reaction rate, Chemistry, General Chemical Engineering, Analytical chemistry, General Chemistry, Growth rate, Thin film, Gas phase
Abstract

水平管型ホットウォールCVD反応器を用い, Zrのβ-ジケトン錯体を原料としてZrO2膜を合成した。反応温度823K～973K, 操作圧0.4kPa～24kPa, 全流量0～1500sccm, 酸素濃度0～50mol%の範囲内で, 成膜条件による膜色, 結晶形および成膜速度の相違を実験的に検討した.気相反応速度定数のみを未知パラメータとして含む基礎方程式群の2次元数値計算をZr (DPM) 4を原料とする上記LPMOCVD系に適用し, 実測したすべての管軸方向成膜速度分布をフィットし得る唯一の気相反応速度定数を決定した.活性化エネルギーとして140kJ/mol程度の値が得られた.正PCVD装置を用いるこの種の解析では, 管内圧力損失が無視し得ないことを示した.

Published
1992

30. Barium Titanate Thin Film Growth by Low-pressure Metalorganic Chemical Vapor Deposition

Author

Sekine, Tetsuaki, Okumura, Yu, Satou, Akira, and Akiyama, Yasunobu

Abstract

Barium titanate (BaTiO3) thin films were prepared from b-diketonate complexes as raw materials (on silicon substrates and into short quartz tubes) in the horizontal tubular hot-wall chemical vapor deposition reactor. The growth conditions, growth rate, and types of films grown were investigated. At high temperature (973 K), BaTiO3 could be prepared at concentrations equal to each of the metalorganic complexes, and its growth rate could be explained by summing the simple oxide growth rates because the growth rate of BaTiO3 is controlled by the mass transfer rate of the precursor. However, at low temperature (773 K), BaTiO3 could grow at a concentration of the Ti source that was richer than that of the Ba source because the growth rate of BaTiO3 is controlled by the rate of the chemical reaction and the Ti source reacts slower than the Ba source.

Published
2009

31. Reaction analysis for ZrO2and Y2O3thin film growth by low-pressure metalorganic chemical vapor deposition using β-diketonate complexes

Author

Akiyama, Yasunobu, Sato, Tsuneyuki, and Imaishi, Nobuyuki

Abstract

A mathematical model was developed for low-pressure metalorganic chemical vapor deposition (LPMOCVD) of ZrO2and Y2O3film growth. Zr(DPM)4(tetrakis-2,2,6,6-tetramethyl-3,5-heptandionate zirconium (β-diketonate complex)) and Y(DPM)3were used as source materials. The surface reaction rate constant (or the reactive sticking coefficient) was determined by comparing the experimentally observed step coverages on micro-scale trenches with those predicted by a simplified Monte Carlo simulation. A gas-phase reaction rate constant was taken as a disposable parameter to fit the growth rate distributions along the reactor tube by a diffusion reaction transport model. Arrhenius-type equations were proposed for both surface and gas phase reactions. For the surface reactions, the activation energies were 188 kJ/mol (T< 909 K) and 38 kJ/mol (T> 909 K) for ZrO2and 133 kJ/mol (T< 870 K) for Y2O3. For the gas phase reactions, they were 140 and 123 kJ/mol for ZrO2and Y2O3, respectively. The scanning electron microscopy (SEM) micrographs and X-ray diffraction (XRD) patterns revealed that the crystallographic orientation and morphology of the grown films depend on the growth temperature.

Published
1995
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