Precrystallization Engineering of Hf<sub>0.5</sub>Zr<sub>0.5</sub>O<sub>2</sub> Film in Back-End-of-Line Compatible Ferroelectric Device for Enhanced Remnant Polarization and Endurance
Yuan Wang, Yang Yang, Pengfei Jiang, Shuxian Lv, Boping Wang, Yuting Chen, Yaxin Ding, Tiancheng Gong, Qing Luo
Abstract
High-performance ferroelectric devices compatible with the Back-End-of-Line (BEOL) process are necessary for their mass production and application. In this letter, pre-crystallization engineering of increasing the number of cycles of ZrO2 and HfO2 in each period of Hf <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{{0.5}}$ </tex-math></inline-formula> Zr0.5O2 (HZO) film growth process was utilized to improve the ferroelectric property of TiN/HZO/TiN capacitors at 400°C annealing process. Grazing incidence X-ray diffraction shows that higher in-situ crystallized tetragonal phase nuclei can be formed in the HZO film with 3 cycles of ZrO2 and 3 cycles of HfO2 (3Z3H) in each period during the ALD step at 280°C, which will enhance the formation of ferroelectric orthorhombic phase after rapid thermal annealing. The developed TiN/3Z3H/TiN capacitor shows high remnant polarization ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2{P}_{r}$ </tex-math></inline-formula> ) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$45 ~\mu \text{C}$ </tex-math></inline-formula> /cm2, and better endurance of more than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{10}}$ </tex-math></inline-formula> cycles.