Bi3.25La0.75Ti3O12 Thin Films Prepared on Pt/Ti/SiO2/Si(100) by Chemical Solution Deposition

초록

Ferroelectric Bi3.25La0.75Ti3O12 (BLT) thin films have been prepared on Pt/Ti/SiO2/Si substrate by chemical solution deposition method. Bismuth acetate, lanthanum acetate, and titanium isopropoxide as precursors of bismuth, lanthanum, and titanium were used. The spin-on films were dried at 300oC for 5 min on a hot plate and were crystallized using either furnace or rapid thermal annealing (RTA). The crystallization temperatures by furnace and RTA were selected as the main experimental parameters. The crystal structure and the degree of crystallization of BLT thin films were examined by the x-ray diffraction (XRD) and the surface morphology was observed by field emission scanning electron microscopy (FESEM). The electrical property (P-V curve) of Pt/BLT/Pt capacitors was measured to compare two different annealing processes. In the case of BLT film annealed by furnace at 650oC for 1 h, remanent polarization and coercive voltage were 11 mC/cm2 and 1.2 V, respectively. BLT film annealed by RTA showed similar Pr value but higher Vc than that annealed by furnace. It was turned out that furnace annealing for the crystallization of BLT films was better heating tool than RTA in achieving better physical and electrical property at low crystallization temperature.