Investigating structural features of Ba and Zr co-substituted strontium bismuth tantalate thin films..

[摘要] Structural (crystal and microstructure), chemical and electronic states, and ferroelectric and electrical features of Ba and Zr co-substituted strontium bismuth tantalate (SBT) were probed in this study. Distinctly, Ba and Zr were substitutedfor Ta and Sr sites of Sr$_{0.8}$Bi$_{2.2}$Ta$_2$O$_9$ in the form of Sr$_{0.8−x}$Ba$_x$ Bi$_{2.2}$Ta$_{2−y}$Zr$_y$O$_9$. To investigate the impact of the co-substitution on the crystal structure, microstructure, ferroelectric and electrical properties, Sr$_{0.8−x}$Ba$_x$ Bi$_{2.2}$Ta$_{2−y}$Zr$_y$O$_9$ thin films were deposited on Pt/Ti/SiO$_2$/Si(100) wafers by sol–gel spin by coating method. Crystal structure, microstructure, chemical and electronic states, ferroelectric, capacitance and leakage current characteristics of the films were studied to investigate potential for one transistor type ferroelectric random access memories (1T-type FeRAMs). Successful substitutions up to 10 mol% lead to reduction of double remanent polarization ($2P_r$) to 10.26 $\ mu$C cm$^{−2}$, and dielectric constant ($\epsilon_r$) to 135. These values demonstrate that successful co-substitution of limited Ba and Zr in SBT with stable crystal structure has the ability to decrease $P_r$ and $\epsilon_r$ values of the ferroelectric material which can be a candidate gate to be utilized inferroelectric field-effect transistors (FeFETs) for 1T-type FeRAM applications.

[学科分类] 材料工程

[关键词] Crystal structure;ion substitution;strontium bismuth tantalate;ferroelectric;thin film. 1. Introduction Owing to superior properties;ferroelectric random access memories (FeRAMs);for instance;those with a metal– ferroelectric–insulator–semiconductor (MFIS) structure have been focussed upon by researchers as a replacement for flash memory and dyna