Ferroelectric properties of sandwich structured (Bi, La)₄T₃O₁₂/Pb(Zr, Ti)O₃/ (Bi, La)₄Ti₃O₁₂thin films on Pt/Ti/SiO₂/Si substrates

Abstract

Sandwich structured (Bi, La)4Ti3O12/Pb(Zr, Ti)O3/(Bi, La)4Ti3O12 thin films were fabricated on Pt/Ti/SiO2/Si substrates, with the intention of simultaneously utilizing the advantages of both (Bi, La)4Ti3O12 (BLT) and Pb(Zr, Ti)O3 (PZT) thin films such as non-fatigue behaviours of BLT and good ferroelectric properties of PZT. Both BLT and PZT layers were prepared by a chemical solution deposition technique. The experiments demonstrated that the sandwich structure showed fatigue-free characteristics at least up to 1010 switching bipolar pulse cycles under 8 V and excellent retention properties. The sandwich structured thin films also exhibited well-defined hysteresis loops with a remanent polarization (2Pr) of 8.8 µC cm-2 and a coercive field (Ec) of 47 kV cm-1. The room-temperature dielectric constant and dissipation factor were 210 and 0.031, respectively, at a frequency of 100 kHz. These results suggest that this sandwich structure is a promising material combination for ferroelectric memory applications.