Thickness dependence of the switching voltage in all-oxide ferroelectric thin-film capacitors prepared by pulsed laser deposition

Abstract

Thin-film ferroelectric capacitors consisting of PbZr0.53Ti0.47O3 sandwiched between La0.5Sr0.5CoO3 electrodes have been deposited using pulsed laser deposition. The combination of oxidic perovskite-type materials results in capacitors with a coercive field (Ec) which is comparable with values for bulk ceramics. Textured thin-film capacitors with a columnar microstructure show lower switching voltages than epitaxial films. No thickness dependence of Ec and a good endurance up to 1011 cycles have been observed for epitaxial as well as textured capacitors with oxidic electrodes. In contrast, capacitors with a metallic top electrode show an increase of Ec with decreasing thickness of the ferroelectric layer. We show that charge injection can explain the experimentally observed increase of Ec 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 the utmost importance for the capacitor quality.