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Journal of the Korean Ceramic Society 1993;30(6): 510. |
다층 구조로부터 열 확산에 의한 $PbTiO_3$ 박막의 제조 |
서도원, 최덕균 |
한양대학교 무기재료공학과 |
Formation of $PbTiO_3$ Thin Films by Thermal Diffusion from Multilayrs |
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ABSTRACT |
$PbTiO_3$ thin films have been formed by rapid thermal annealing(RTA) of $TiO_2$/Pb/$TiO_2$ multilayer films deposited on Si wafers by RF sputtering. Based on the optimal depositon conditions of TiO2 and Pb, $TiO_2$/Pb/$TiO_2$ three layers were deposited for 900$AA$ each. These films were subjected to RTA process at the temperatures ranging from $400^{circ}C$ to $900^{circ}C$ for 30 seconds in air, and were analyzed by X-ray diffraction and transmission electron microscopy to investigate the phases and the microstructures. As a result, perovskite $PbTiO_3$ phases was obtained above $500^{circ}C$ with the trace of unreacted $TiO_2$. RBS analysis revealed the anisotropic behavior of diffusion that the diffusivity of Pb to the bottom $TiO_2$ layer was faster than that of Pb to the top $TiO_2$ layer. The amorphous Pb-silicate was formed between film and Si substrate due to the diffusion of Pb, but Pb-silicate existed locally at the interface and the amount of that phase was very small. Therefore the effect of bottom $TiO_2$ layer as a diffusion barrier was confirmed. $PbTiO_3$ films formed by current technique showed a relative dielectric constant of 60, and the maximum breakdown field reached 170kV/cm. |
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