In this work, ultrathin pure HfO_2 and Al-doped HfO_2films(about 4-nm thick) are prepared by atomic layer deposition and the crystallinities of these films before and after annealing at temperatures ranging from 550℃...In this work, ultrathin pure HfO_2 and Al-doped HfO_2films(about 4-nm thick) are prepared by atomic layer deposition and the crystallinities of these films before and after annealing at temperatures ranging from 550℃ to 750℃ are analyzed by grazing incidence x-ray diffraction. The as-deposited pure HfO_2 and Al-doped HfO_2 films are both amorphous. After550-℃ annealing, a multiphase consisting of a few orthorhombic, monoclinic and tetragonal phases can be observed in the pure HfO_2 film while the Al-doped HfO_2 film remains amorphous. After annealing at 650℃ and above, a great number of HfO_2 tetragonal phases, a high-temperature phase with higher dielectric constant, can be stabilized in the Al-doped HfO_2 film. As a result, the dielectric constant is enhanced up to about 35. The physical mechanism of the phase transition behavior is discussed from the viewpoint of thermodynamics and kinetics.展开更多
基金Project supported by the National High Technology Research and Development Program of China(Grant No.2015AA016501)the National Natural Science Foundation of China(Grant Nos.61574168 and 61504163)
文摘In this work, ultrathin pure HfO_2 and Al-doped HfO_2films(about 4-nm thick) are prepared by atomic layer deposition and the crystallinities of these films before and after annealing at temperatures ranging from 550℃ to 750℃ are analyzed by grazing incidence x-ray diffraction. The as-deposited pure HfO_2 and Al-doped HfO_2 films are both amorphous. After550-℃ annealing, a multiphase consisting of a few orthorhombic, monoclinic and tetragonal phases can be observed in the pure HfO_2 film while the Al-doped HfO_2 film remains amorphous. After annealing at 650℃ and above, a great number of HfO_2 tetragonal phases, a high-temperature phase with higher dielectric constant, can be stabilized in the Al-doped HfO_2 film. As a result, the dielectric constant is enhanced up to about 35. The physical mechanism of the phase transition behavior is discussed from the viewpoint of thermodynamics and kinetics.
基金financially supported by the National Natural Science Fund for Distinguished Young Scholars(21925506)the National Natural Science Foundation of China(U21A20331 and 81903743)+5 种基金Ningbo S&T Innovation 2025 Major Special Programme(2018B10055)CAS Key Project of Frontier Science Research(QYZDBSSW-SYS030)Ningbo Natural Science Foundation(2021J192)Ningbo Key Scientific and Technological Project(2022Z117)Ningbo Public Welfare Science and Technology Planning Project(2021S149)ZBTI Scientific Research Innovation Team(KYTD202105)。
基金supported by the National Natural Science Foundation of China(21203008 and 21975025)Beijing Natural Science Foundation(2172051)the State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University。
基金financially supported by the Basic and Applied Basic Research Major Program of Guangdong Province(2019B030302007)the National Natural Science Foundation of China(51873217,21734008,51703228,51961135103,51773047 and 51903239)。
