Pulsed excimer laser ablation of (Pb,La)TiO₃ thin films for dynamic random access memory devices

Abstract

Polycrystalline (Pb,La)TiO3 thin films were deposited by pulsed excimer laser ablation on Si and Pt coated Si substrates. The crystallinity of the films showed dependence on the annealing temperature and oxygen pressure during ablation. Similar trends reflected in the dielectric behavior in terms of varying dielectric permittivity between 430-620 as the ablation pressure varied between 1 and 100 mTorr. Films exhibited the presence of ferroelectricity in terms of hysteresis in capacitance-voltage characteristic in a metal-ferroelectric-metal configuration. The charge storage density estimated from the polarization measurements was about 10 µ C/cm², while a leakage current density of 10^-8 A/cm² was observed at an applied field of 100 kV/cm.