EFFECTS OF O2 GAS ON REACTION MECHANISMS IN THE CHEMICAL VAPOR DEPOSITION OF (Ba, Sr)TiO3 THIN FILM

• Published in: Jpn.J.Appl.Phys ,Part 1. Vol. 41, no. 4A, pp. 2231-2240. 2002 Part 1. Vol. 41, no. 4A, pp. 2231-2240. 2002, 2002, Vol.41 (4A), p.2231-2240
• Main Authors: Yamamuka, M, Momose, S, Nakamura, T, Tachibana, K, Takada, H
• Format: Article
• Language: English
• ISSN: 0021-4922
• DOI: 10.1143/JJAP.41.2231

Effects of O2 gas on reaction mechanisms in the CVD of (Ba, Sr)TiO3 [BST] film were studied by investigating the atomic incorporation rates of Ba, Sr, and Ti. The atomic incorporation rates were measured using an XRF method for BST film prepared for several molar source supply ratios with different O2 flow rates of 0.1, 0.5, and 1.0 slm. In the experiments, these rates increased monotonically with increasing O2 flow rate in flux regions where incorporation reactions might be dominated kinetically. This suggested that the supplied O2 gas might affect the adsorption of film precursors onto the film surface in the CVD of BST. From the obtained experimental results, authors proposed a CVD model, in which some precursors adsorbed on the film surface form adsorptive sites, and that successive precursors are adsorbed thereon. The supplied O2 gas contributes to the formation of the adsorptive sites; the Ba and Sr precursors release their own O and receive O from the supplied O2 gas, and then the oxidized precursors form adsorptive sites. On the other hand, the Ti precursors form adsorptive sites by holding their own O on the film surface. Then, under the proposed model, atomic incorporation rates and overall sticking coefficients for BST film depositions were numerically calculated. The calculated results were in good agreement with the experimental results for several molar source ratios with different O2 flow rates of 0.1, 0.5, and 1.0 slm. 22 refs.