Improved remnant polarization of Zr-doped HfO2 ferroelectric film by CF4/O2 plasma passivation

Yejoo Choi; Hyeonjung Park; Changwoo Han; Jinhong Min; Changhwan Shin

doi:10.1038/s41598-022-21263-8

Improved remnant polarization of Zr-doped HfO₂ ferroelectric film by CF₄/O₂ plasma passivation

Sci Rep. 2022 Oct 6;12(1):16750. doi: 10.1038/s41598-022-21263-8.

Authors

Yejoo Choi^#¹, Hyeonjung Park^#¹, Changwoo Han¹, Jinhong Min², Changhwan Shin³

Affiliations

¹ Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon, 16419, South Korea.
² Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI, 48109, USA.
³ School of Electrical Engineering, Korea University, Seoul, 02841, South Korea. cshin@korea.ac.kr.

^# Contributed equally.

Abstract

In this work, the impact of fluorine (CF₄) and oxygen (O₂) plasma passivation on HfZrO_x (HZO) based ferroelectric capacitor was investigated. By the fluorine passivation, the surface trap density and oxygen vacancies in the HZO-based Metal-ferroelectric-insulator-semiconductor (MFIS) capacitors were suppressed, resulting in the increased pristine remnant polarization (2P_r). The pristine value (2P_r) of baseline samples annealed at 500 °C and 600 °C were 11.4 µC/cm² and 24.4 µC/cm², respectively. However, with the F-passivation, the 2P_r values were increased to 30.8 µC/cm² and 48.2 µC/cm² for 500 °C and 600 °C, respectively. The amount of surface defects and oxygen vacancies are quantitatively confirmed by the conductance method and XPS analysis. However, due to the incorporation of fluorine atoms into the ferroelectric-insulator films, undesirable degradation on endurance characteristics were observed.

Grants and funding

2020R1A2C1009063/National Research Foundation of Korea