ELECTRICAL-PROPERTIES OF LEAD LANTHANUM TITANATE THIN-FILM CAPACITORSPREPARED BY SOL-GEL METHOD

High-quality (Pb1-xLax)Ti1-x/4O3 (x=0.05) [PLT] thin films were fabric ated successfully by sol-gel processing onto Pt/Ti/SiO2/Si and p-Si su bstrates. The optimum route and the conditions for preparing homogeneo us and crack-free thin films mere systematically investigated. Ferroel ectric perovskite phase was observed in the PLT thin films annealed at 600 degrees C for 30 min. We studied the electrical properties of the PLT film capacitors with the metal-ferroelectric-metal (MFM) and the metal-ferroelectric-semiconductor (MFS) structure for use in ferroelec tric memories. The dielectric constant and dissipation factor measured for MFM capacitor were 225 and 0.018 at 100 kHz, respectively. The re manent polarization (P-r) and coercive field (E(c)) of the PLT film we re 8.5 mu C/cm(2) and 110 kV/cm. respectively. Also the film with 600 nm thickness showed current density as low as 10(-6) A/cm(2) at the el ectric field of 200 kV/cm, which corresponds to the electric resistivi ty of similar to 10(12) (Omega . cm) and represents excellent insulati ng properties. The MFS capacitor showed ferroelectric switching proper ties in C-V characteristics and the memory window of the hysteresis lo op was about 1 V in the operation of +/-10 V.