Improved remnant polarization of Zr-doped HfO2 ferroelectric film by CF4/O-2 plasma passivation

Abstract

In this work, the impact of fluorine (CF4) and oxygen (O-2) plasma passivation on HfZrOx (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 degrees C and 600 degrees C were 11.4 mu C/cm(2) and 24.4 mu C/cm(2), respectively. However, with the F-passivation, the 2P(r) values were increased to 30.8 mu C/cm(2) and 48.2 mu C/cm(2) for 500 degrees C and 600 degrees 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.