Chemical and Microstructural Characterization of Rf-sputtered BaTiO₃ Nano-capacitors with Ni Electrodes

Abstract

Chemical and microstructural evaluation techniques have been used to characterize sputter deposited 100-150 nm thick BaTiO3 nano-capacitors with 30 nm thick Ni electrodes fabricated on Si/SiO2 wafers. More than 99% of devices had resistance > 20 MΩ. Electrodes were found to have a roughness, Ra, of about 0.66 ± 0.04 nm, and the BaTiO3 had a Ra value of 1.3 ± 0.12 nm. Characterization of the BaTiO3 film chemistry with X-ray Photoelectron Spectroscopy (XPS) showed the films had excess oxygen and Ba:Ti ratios ranging from 0.78 to 1.1, depending on sputtering conditions. X-ray diffraction showed a broad peak between approximately 20° and 35° 2θ, indicating the films were either amorphous or contained grain sizes less than 5 nm. Focused ion beam images confirmed the presence of smooth, conformal films, with no visible signs of macro-defects such as pin-holes, cracks, or pores. High resolution transmission electron microscopy (TEM) and electron diffraction patterns confirmed the presence of a nearly amorphous film with limited short range order. No correlation was found between the chemical and microstructural studies with the dielectric permittivity (280-1000), loss (0.02-0.09), and/or resistivity (8.7 × 1010-1.5 × 1012 Ω cm) values.

Department(s)

Materials Science and Engineering

Keywords and Phrases

Sputtering; Capacitors; Nano-Technology; Dielectric

International Standard Serial Number (ISSN)

0169-4332

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2012 Elsevier, All rights reserved.

Publication Date

01 May 2012

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