Thickness dependence of the ferroelectric characteristics of SBT and SBTN thin films

Abstract

SrBi_2.4Ta₂O₉ (SBT) and SrBi_2.4(Ta_0.75Nb_0.25)₂O₉ (SBTN) thin films were prepared using LSMCD and MOD processes, respectively, and their ferroelectric properties were characterized with variation of the film thickness. The LSMCD-derived SBT film of 70 nm thickness exhibited the 2P_r of 15.9 μC/cm² and E_c of 69 kV/cm at ±5 V. Within the thickness range of 70∼410 nm, the SBT and SBTN films exhibited the size effects, i.e., a decrease of the remanent polarization and the relative permittivity and an increase of the coercive field with a reduction of the film thickness. The SBT and SBTN films of 70∼410 nm thickness exhibited the fatigue-free behavior up to 10¹² switching cycles.

Key Words:

• SBT
• SBTN
• thin film
• ferroelectric properties
• thickness dependence
• size effects