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Nucleation‐Limited Ferroelectric Orthorhombic Phase Formation in Hf 0.5 Zr 0.5 O 2 Thin Films
Author(s) -
Lee Young Hwan,
Hyun Seung Dam,
Kim Hae Jin,
Kim Jun Shik,
Yoo Chanyoung,
Moon Taehwan,
Kim Keum Do,
Park Hyeon Woo,
Lee Yong Bin,
Kim Baek Su,
Roh Jangho,
Park Min Hyuk,
Hwang Cheol Seong
Publication year - 2019
Publication title -
advanced electronic materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.25
H-Index - 56
ISSN - 2199-160X
DOI - 10.1002/aelm.201800436
Subject(s) - materials science , monoclinic crystal system , nucleation , tetragonal crystal system , ferroelectricity , tin , thin film , phase (matter) , orthorhombic crystal system , annealing (glass) , kinetic energy , activation energy , crystallography , thermodynamics , nanotechnology , chemistry , dielectric , metallurgy , optoelectronics , crystal structure , physics , organic chemistry , quantum mechanics
Various possibilities have been proposed as the cause of the doped‐ or undoped‐HfO 2 thin film materials showing unusual ferroelectricity. These assumptions are based on empirical results, yet finding the origin of the unprecedented ferroelectricity within HfO 2 has suffered from a serious gap between its theoretical calculation, mostly based on thermodynamic approach and the actual experimental results. To fill the gap, this study proposes to consider the kinetic energy, providing the evidence of the kinetic energy barrier upon a phase transformation from the tetragonal phase to the monoclinic phase affected by the TiN top electrode (capping layer). 10 nm thick Hf 0.5 Zr 0.5 O 2 thin films are deposited and annealed with or without the TiN capping layer with subsequent annealing at different time and temperature. Arrhenius plot is constructed to obtain the activation energy for the tetragonal‐to‐monoclinic phase transformation by calculating the amount of the transformed phase using X‐ray diffraction pattern. Johnson–Mehl–Avrami and nucleation‐limited transformation models are utilized to describe the characteristic nucleation and growth time and calculate the activation energy for the monoclinic phase transformation of the Hf 0.5 Zr 0.5 O 2 thin film. Both models demonstrate that the TiN capping layer provides a kinetic energy barrier for tetragonal‐to‐monoclinic phase transformation and enhances the ferroelectric property.