THICKNESS DEPENDENCE OF THE SWITCHING VOLTAGE IN ALL-OXIDE FERROELECTRIC THIN-FILM CAPACITORS PREPARED BY PULSED-LASER DEPOSITION

Thin-film ferroelectric capacitors consisting of PbZr0.53Ti0.47O3 sand wiched between La0.5Sr0.5CoO3 electrodes have been deposited using pul sed laser deposition. The combination of oxidic perovskite-type materi als results in capacitors with a coercive field (E(c)) which is compar able with values for bulk ceramics. Textured thin-film capacitors with ;a columnar microstructure show lower switching voltages than epitaxia l films. No thickness dependence of E(c) and a good endurance up to 10 (11) cycles have been observed for epitaxial as well as textured capac itors with oxidic electrodes. In contrast, capacitors with a metallic top electrode show an increase of E(c) with decreasing thickness of th e ferroelectric layer. We show that charge injection can explain the e xperimentally observed increase of E(c) with decreasing ferroelectric layer thickness. An overview is given of the growth conditions needed for PbZr0.53Ti0.47O3 films, because the precise stoichiometry is-of th e utmost importance for the capacitor quality. (C) 1997 American Insti tute of Physics.