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Dielectric behavior related to TiOx phase change to TiO2 in TiOx/Al2O3 nanolaminate thin films

Published online by Cambridge University Press:  13 May 2014

Geunhee Lee*
Affiliation:
Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080; Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931-3343
Ram S. Katiyar
Affiliation:
Institute for Functional Nanomaterials, University of Puerto Rico, San Juan, Puerto Rico 00931-3343
Bo-Kuai Lai
Affiliation:
Lake Shore Cryotronics, Westerville, Ohio 43082
Charudatta Phatak
Affiliation:
Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439
Orlando Auciello*
Affiliation:
Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080
*
Address all correspondence to Geunhee Lee at[email protected]and Orlando Auciello[email protected]
Address all correspondence to Geunhee Lee at[email protected]and Orlando Auciello[email protected]
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Abstract

We previously demonstrated that TiOx/Al2O3 nanolaminates (TAO NL) exhibit abnormally high-dielectric constant k (800–1000), due to Maxwell–Wagner polarization, via charge accumulation at insulating Al2O3/semiconducting TiOx interfaces. Here, we report TAO NL dielectric properties related to TiOx phase change in TiOx (0.9 nm)/Al2O3 (0.1 nm) NL. High-resolution transmission electron microscopy shows amorphous TiOx phase change to crystalline anatase TiO2 due to free-energy minimization. The phase change induce reduction in leakage current and dielectric loss (J = 10−2 to 10−4 A/cm2, tan δ = 10 to 10−1), still with k ~ 600 up to MHz, compared to amorphous TAO NLs.

Type
Research Letters
Copyright
Copyright © Materials Research Society 2014 

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