Precrystallization Engineering of Hf0.5Zr0.5O2 Film in Back-End-of-Line Compatible Ferroelectric Device for Enhanced Remnant Polarization and Endurance

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 $_{{0.5}}$ 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 ( $2{P}_{r}$ ) of $45 ~\mu \text{C}$ /cm2, and better endurance of more than $10^{{10}}$ cycles.