Correlation between ferroelectricity and ferroelectric orthorhombic phase of HfxZr1−xO2 thin films using synchrotron x-ray analysis
Takashi Onaya,
Toshihide Nabatame,
Yong Chan Jung,
Heber Hernandez-Arriaga,
Jaidah Mohan,
Harrison Sejoon Kim,
Naomi Sawamoto,
Chang-Yong Nam,
Esther H. R. Tsai,
Takahiro Nagata,
Jiyoung Kim,
Atsushi Ogura
Affiliations
Takashi Onaya
Department of Electrical Engineering, Graduate School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
Toshihide Nabatame
National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
Yong Chan Jung
Department of Materials Science and Engineering, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
Heber Hernandez-Arriaga
Department of Materials Science and Engineering, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
Jaidah Mohan
Department of Materials Science and Engineering, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
Harrison Sejoon Kim
Department of Materials Science and Engineering, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
Naomi Sawamoto
Meiji Renewable Energy Laboratory, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
Chang-Yong Nam
Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
Esther H. R. Tsai
Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
Takahiro Nagata
National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
Jiyoung Kim
Department of Materials Science and Engineering, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080, USA
Atsushi Ogura
Department of Electrical Engineering, Graduate School of Science and Technology, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
The change in the interplanar spacing (d-spacing) including the ferroelectric orthorhombic (O) phase in the low-temperature fabricated HfxZr1−xO2 (HZO) films was studied using synchrotron grazing-incidence wide-angle x-ray scattering analysis. The 10-nm-thick HZO films were fabricated by thermal and plasma-enhanced atomic layer deposition (TH- and PE-ALD) methods using H2O gas and O2 plasma as oxidants, respectively, and a post-metallization annealing (PMA) was performed at 300–400 °C. The d-spacing of the mixture of (111)-, (101)-, and (111)-planes of O, tetragonal (T), and cubic (C) phases, respectively, for the TH- and PE-ALD HZO films increased up to 2.99 Å with an increase in PMA temperature, while the d-spacing estimated by conventional x-ray diffraction was 2.92 Å regardless of the PMA temperature. The remanent polarization (2Pr = Pr+ − Pr−) of the HZO films increased as the PMA temperature increased. It is clear that the 2Pr value satisfied a linear relationship as a function of the d-spacing of O(111)/T(101)/C(111) phases. Furthermore, the wake-up effect was found to depend on the ferroelectric O phase formation. The wake-up effect was significantly reduced in both the TH- and PE-ALD HZO films after the PMA at 400 °C due to the increase in the ferroelectric O phase formation. The leakage current density (J)–electric field properties of the PE-ALD HZO film with the lowest d-spacing were divided into three steps, such as low, middle, and large J values, in the wake-up (103 cycles), pristine (100 cycle), and fatigue (107 cycles) states, respectively. Therefore, an analysis of the ferroelectric O phase is very important for understanding the ferroelectricity including endurance.
