TY - JOUR
T1 - Ferroelectricity in dopant-free HfO2 thin films prepared by pulsed laser deposition
AU - Luo, Yongjian
AU - Tang, Zhenxun
AU - Yin, Xiaozhe
AU - Chen, Chao
AU - Fan, Zhen
AU - Qin, Minghui
AU - Zeng, Min
AU - Zhou, Guofu
AU - Gao, Xingsen
AU - Lu, Xubing
AU - Dai, Jiyan
AU - Chen, Deyang
AU - Liu, Jun Ming
N1 - Funding Information:
This work was supported by the National Natural Science Foundation of China (Grant Nos. U1832104 and 91963102 ) and the Research Grants Council of Hong Kong (Project No. 15300619 ). Authors also acknowledge the financial support of Guangdong Science and Technology Project-International Cooperation (Grant No. 2019A050510036 ) and the Natural Science Foundation of Guangdong Province (Grant No. 2020A1515010736 ). D.C. thanks the financial support from Guangdong Provincial Key Laboratory of Optical Information Materials and Technology (No. 2017B030301007 ), Department of Education of Guangdong Province (No. 2019KTSCX032 ) and the Hong Kong Scholars Program (Grant No. XJ2019006 ).
Publisher Copyright:
© 2021 The Chinese Ceramic Society
PY - 2022/3
Y1 - 2022/3
N2 - As a high-k material, hafnium oxide (HfO2) has been used in gate dielectrics for decades. Since the discovery of polar phase in Si-doped HfO2 films, chemical doping has been widely demonstrated as an effective approach to stabilize the ferroelectric phase in HfO2 based thin films. However, the extra capping layer deposition, post-growth annealing and wake-up effect are usually required to arouse the ferroelectricity in HfO2 based thin films, resulting in the increase of complexity for sample synthesis and the impediment of device application. In this study, the ferroelectricity is observed in non-capped dopant-free HfO2 thin films prepared by pulsed laser deposition (PLD) without post-growth annealing. By adjusting the deposited temperature, oxygen pressure and thickness, the maximum polarization up to 14.7 μC/cm2 was obtained in 7.4 nm-thick film. The fraction of orthorhombic phase, concentrations of defects and size effects are considered as possible mechanisms for the influences of ferroelectric properties. This study indicates that PLD is an effective technique to fabricate high-quality ferroelectric HfO2 thin films in the absence of chemical doping, capping layer deposition and post-growth annealing, which may boost the process of nonvolatile memory device application.
AB - As a high-k material, hafnium oxide (HfO2) has been used in gate dielectrics for decades. Since the discovery of polar phase in Si-doped HfO2 films, chemical doping has been widely demonstrated as an effective approach to stabilize the ferroelectric phase in HfO2 based thin films. However, the extra capping layer deposition, post-growth annealing and wake-up effect are usually required to arouse the ferroelectricity in HfO2 based thin films, resulting in the increase of complexity for sample synthesis and the impediment of device application. In this study, the ferroelectricity is observed in non-capped dopant-free HfO2 thin films prepared by pulsed laser deposition (PLD) without post-growth annealing. By adjusting the deposited temperature, oxygen pressure and thickness, the maximum polarization up to 14.7 μC/cm2 was obtained in 7.4 nm-thick film. The fraction of orthorhombic phase, concentrations of defects and size effects are considered as possible mechanisms for the influences of ferroelectric properties. This study indicates that PLD is an effective technique to fabricate high-quality ferroelectric HfO2 thin films in the absence of chemical doping, capping layer deposition and post-growth annealing, which may boost the process of nonvolatile memory device application.
KW - Ferroelectricity
KW - Hafnium oxide
KW - Orthorhombic phase
KW - Pulsed laser deposition
UR - http://www.scopus.com/inward/record.url?scp=85117164039&partnerID=8YFLogxK
U2 - 10.1016/j.jmat.2021.09.005
DO - 10.1016/j.jmat.2021.09.005
M3 - Journal article
AN - SCOPUS:85117164039
SN - 2352-8478
VL - 8
SP - 311
EP - 318
JO - Journal of Materiomics
JF - Journal of Materiomics
IS - 2
ER -