| Autor: |
Yamamuka, Mikio, Kawahara, Takaaki, Makita, Tetsuro, Akimasa Yuuki, Akimasa Yuuki, Kouichi Ono, Kouichi Ono |
| Zdroj: |
Japanese Journal of Applied Physics; February 1996, Vol. 35 Issue: 2 p729-729, 1p |
| Abstrakt: |
Thermal desorption characteristics of (Ba, Sr)TiO3[BST] thin films prepared by metalorganic chemical vapor deposition (CVD) using liguid sources have been studied, together with their crystallinity and electrical properties. Thermal desorption was observed for CO2at 400° C and 900° C, and CO at 600° C. The intensities of the CO2peaks at 400° C and 900° C increased with the increasing atomic composition ratio of (Ba+Sr)/Ti, in relation to the excess Ba and Sr in the BST films; in particular, the CO2peak at 900° C may originate from BaCO3and/or SrCO3lumps formed in the films, and the CO2peak at 400° C may be attributed to gases adsorbed on the sites of contaminants such as BaOxand/or SrOxin films, due to excess Ba and Sr coming from the atmosphere after deposition. On the other hand, the CO peak at 600° C occurred most strongly from BST films with high dielectric constants at (Ba+Sr)/Ti?1, or perovskite crystalline structures having large grains. Moreover, the desorption of CO at 600° C was also observed from films kept in the atmosphere after annealed above 600° C in vacuum. These results imply that the BST crystalline perovskite grains may have adsorption sites for CO from the atmosphere. |
| Databáze: |
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