抄録
Annealing process of Y2O3 thin film produced by metal organic decomposition method was analyzed by x-ray reflectivity (XRR), x-ray diffraction (XRD), and atomic force microscopy. The annealing process was divided into two stages, stage I and stage II with respect to the annealing time. In the stage I, nuclei of Y2O3 nano-crystals were scatteringly formed in the Y-O precursor film just after the temperature rising. As the annealing progresses, expanding nano-crystals filled up the film and covered the surface smoothly, resulting in a clear XRR oscillation. From XRD analyses, volume-weighted average diameter of the nano-crystals to produce the smooth surface was estimated to be ~ 10 nm. In the following stage 11, the Y2O3 nano-crystals did not expand any more; the crystals did not make a large domain by bunching. On the other hand, degenerative XRR oscillation in stage II revealed that stress at the grain boundary forces up the nano-crystals, resulting in rough interface and/or surface of Y2O3 thin film. Besides that, XRD peak was shifted to higher angle in this stage, indicating that the surface energy of the Y2O3 nano-crystals was so small that the crystal lattice was compressed without release of the internal energy.
