Polaron-electron assisted giant dielectric dispersion in SrZrO{sub 3} high-k dielectric

Journal Article · Tue Jun 07 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4952710· OSTI ID:22596749

Borkar, Hitesh; Barvat, Arun; Pal, Prabir; Kumar, Ashok ^[1]; Shukla, A. K. ^[1]; Pulikkotil, J. J. ^[1]

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1. CSIR-National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India)

The SrZrO{sub 3} is a well known high-k dielectric constant (∼22) and high optical bandgap (∼5.8 eV) material and one of the potential candidates for future generation nanoelectronic logic elements (8 nm node technology) beyond silicon. Its dielectric behavior is fairly robust and frequency independent till 470 K; however, it suffers a strong small-polaron based electronic phase transition (T{sub e}) linking 650 to 750 K. The impedance spectroscopy measurements revealed the presence of conducting grains and grain boundaries at elevated temperature which provide energetic mobile charge carriers with activation energy in the range of 0.7 to 1.2 eV supporting the oxygen ions and proton conduction. X-ray photoemission spectroscopy measurements suggest the presence of weak non-stoichiometric O{sup 2−} anions and hydroxyl species bound to different sites at the surface and bulk. These thermally activated charge carriers at elevated temperature significantly contribute to the polaronic based dielectric anomaly and conductivity. Our dielectric anomaly supports pseudo phase transition due to high degree of change in ZrO{sub 6} octahedral angle in the temperature range of 650–750 K, where electron density and phonon vibration affect the dielectric and conductivity properties.

• OSTI ID: 22596749
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 21; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACTIVATION ENERGY
ANIONS
DIELECTRIC MATERIALS
DISPERSIONS
ELECTRON DENSITY
ELECTRONS
GRAIN BOUNDARIES
HYDROXIDES
OXYGEN
OXYGEN IONS
PERMITTIVITY
PHASE TRANSFORMATIONS
PHONONS
PHOTOELECTRON SPECTROSCOPY
PHOTOEMISSION
POLARONS
PROTONS
SILICON
TEMPERATURE RANGE 0400-1000 K
ZIRCONIUM OXIDES