Enhanced ferroelectric switching speed of Si-doped HfO2 thin film tailored by oxygen deficiency

Investigations concerning oxygen deficiency will increase our understanding of those factors that govern the overall material properties. Various studies have examined the relationship between oxygen deficiency and the phase transformation from a nonpolar phase to a polar phase in HfO 2 thin films....

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Bibliographic Details
Published in:Scientific reports 2021-03, Vol.11 (1), p.6290-6290, Article 6290
Main Authors: Lee, Kyoungjun, Park, Kunwoo, Lee, Hyun-Jae, Song, Myeong Seop, Lee, Kyu Cheol, Namkung, Jin, Lee, Jun Hee, Park, Jungwon, Chae, Seung Chul
Format: Article
Language:English
Subjects:
639/301/119/995
639/301/119/996
Annealing
Energy
High temperature
Humanities and Social Sciences
Low temperature
Monte Carlo simulation
multidisciplinary
Oxygen
Polarization
Science
Science (multidisciplinary)
Spectroscopy
Thin films
Transmission electron microscopy
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Summary:Investigations concerning oxygen deficiency will increase our understanding of those factors that govern the overall material properties. Various studies have examined the relationship between oxygen deficiency and the phase transformation from a nonpolar phase to a polar phase in HfO 2 thin films. However, there are few reports on the effects of oxygen deficiencies on the switching dynamics of the ferroelectric phase itself. Herein, we report the oxygen- deficiency induced enhancement of ferroelectric switching properties of Si-doped HfO 2 thin films. By controlling the annealing conditions, we controlled the oxygen deficiency concentration in the ferroelectric orthorhombic HfO 2 phase. Rapid high-temperature (800 °C) annealing of the HfO 2 film accelerated the characteristic switching speed compared to low-temperature (600 °C) annealing. Scanning transmission electron microscopy and electron energy-loss spectroscopy (EELS) revealed that thermal annealing increased oxygen deficiencies, and first-principles calculations demonstrated a reduction of the energy barrier of the polarization flip with increased oxygen deficiency. A Monte Carlo simulation for the variation in the energy barrier of the polarization flipping confirmed the increase of characteristic switching speed.
ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-021-85773-7