Effects of tantalum adhesion layer on the properties of SrBi2Ta2O9 ferroelectric thin films

Ching Chich Leu*, Ming Che Yang, Chen Ti Hu, Chao-Hsin Chien, Ming Jui Yang, Tiao Yuan Huang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

The effects of tantalum (Ta) adhesion layer on the ferroelectric and microstructural properties of sol-gel-derived SrBi2Ta2O9 (SBT) films are reported in this study. Compared to the traditional titanium (Ti) adhesion layer, the Ta adhesion layer results in more favorable, highly (115) textural structure of SBT films and therefore higher polarization and dielectric constant. The remnant polarization value of the SBT films crystallized at 750 °C increases from 11.1 to 14.2 μC/cm2 at 5 V, and the dielectric constant increases from 175 to 225. The observed improvement in the electrical properties of SBT films is ascribed to the superior microstructure of Pt thin film on Ta, which has been characterized by x-ray diffraction spectrum (XRD). XRD patterns clearly indicate that the Ti adhesion layer favors c-axis crystalline structure that is undesirable for ferroelectric properties. Moreover, secondary ion mass spectrometer profiles strongly indicate that Ti atoms diffuse deeply into the bulk of SBT thin films after crystallization annealing. By using Ta as the adhesion layer material, this inhomogeneous interdiffusion phenomenon can be effectively suppressed, eliminating the formation of TiOx interfacial layer, and possibly decreasing the occurrence of undesirable second phase compound.

Original languageEnglish
Pages (from-to)3833-3835
Number of pages3
JournalApplied Physics Letters
Volume79
Issue number23
DOIs
StatePublished - 3 Dec 2001

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