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The Microstructure and Properties of Layered Oxide Thin Films Fabricated by MOCVD

Published online by Cambridge University Press:  10 February 2011

Seshu B. Desu
Affiliation:
Department of Materials Science and Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
Masaya Nagata
Affiliation:
Functional Devices Laboratories, Sharp Corporation, Chiba 277, Japan
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Abstract

For the first time, layered oxide thin films of SrBi2Ta2O9 (SBT) with very good ferroelectric properties have been prepared by direct-liquid-injection MOCVD technique. The SBT films were deposited onto both Pt/Ti/SiO2/Si wafers and single-crystal sapphire substrates to measure their phase formation, microstructure and ferroelectric properties. Crystalline SBT phase had been observed at temperatures as low as 500°C. With increasing deposition temperature above 500°C, the grain size of SBT thin films was increased from 0.01 μ m to 0.2 μm. The films were found to be dense and homogenous. Typically, SBT thin films of 200 nm thick with grain size about 0. 1μm have 2Pr around 10 μC/cm2 at 5V, Ec 55.7 kV/cm, and dielectric constant around 100. The leakage 9 2 currents were as low as 8 × 10−9 A/cm2 at 150 kV/cm. The films also showed fatigue-free characteristics: no fatigue was observed up to 1.4 × 1010 switching cycles. This development of MOCVD technique for good quality SBT films make their integration into high density nonvolatile memories relatively easy.

Type
Research Article
Copyright
Copyright © Materials Research Society 1996

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