Role of interfacial diffusion in SrBi2Ta2O9 thin-film capacitors

✍ Scribed by Ai-Dong Li; Di Wu; Hui-Qin Ling; Tao Yu; Zhi-Guo Liu; Nai-Ben Ming

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 322 KB
• Volume: 66
• Category: Article
• ISSN: 0167-9317
• DOI: 10.1016/s0167-9317(02)00979-6

✦ Synopsis

SrBi Ta O (SBT) thin films were prepared on Pt / TiO / SiO / Si substrates by metalorganic decomposition 2 2 9 2 2 method. Impact of interfacial diffusion on structural and electrical properties of SBT film capacitors has been investigated by X-ray diffraction (XRD), scanning electron microscopy, Auger electron spectroscopy (AES) and electrical measurements. Interfacial layer model was used to fit measured electrical properties. XRD results confirm the interfacial diffusion leads to secondary phase formation such as Bi Pt and Bi Ti O (BTO) 2 4 3 1 2

between SBT films and Pt and the main interfacial phase is BTO. The electrical measurements indicate that moderate interfacial diffusion acts as a stable barrier layer with the enhanced breakdown voltage and the decreased leakage current whereas remnant polarization decreases slightly and coercive field increases slightly.

Films with moderate interfacial diffusion show good fatigue behavior and retention property. However, the severe interfacial diffusion deteriorates the electrical properties, leading to small remnant polarization and dielectric constant of SBT capacitors.