The atomic scale structure and dynamics characteristics of amorphous SrTiO 3 was simulated by molecular dynamics with potential function including Coulomb interaction, short range repulsion potential, Van der Waals interaction and Morse potential. From the energy and volume's dramatic increase during heating, the melting point was estimated to be about 2440 K, in good agreement with the experimental value. The amorphous SrTiO 3 was obtained by quenching the liquid to room temperature. The correlation function and coordination numbers of the crystalline, liquid, and amorphous states were analyzed. The diffusion coefficients at various temperatures calculated from the auto correlation function of velocity verified that the melting occurred at 2440 K.
The rapid thermal annealing (RTA) process was adapted to crystallize the amorphous (Ba,Sr)TiO 3 thin films prepared on Si(111) substrates by RF magnetic sputtering deposition. The effect of annealing temperature, heating rate and duration time on crystallization was studied through X-ray diffraction and atomic force microscopy. The result shows that the crystallinity and grain size were strongly dependent on the temperature, heating rate, and duration time. Higher heating rate leads to smaller grain size. In high heating rate, the grain size shows different dependence of temperature from that of low heating rate. For a heating rate of 50 • C/s, the grain size decreased with temperature increasing below 700 • C, while after that temperature, the grain size increased slightly with the temperature increasing. At a certain temperature, the crystallinity and surface roughness improved with increase in annealing time, while grain size changed little. The effect of rapid heating rate on the nucleation and grain growth has been discussed, which contributes to the limited grain size of the annealed (Ba,Sr)TiO 3 thin films.
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