Investigation of ionizing radiation mechanisms on HfO₂-based ferroelectric thin-film memories with various configurations

The γ-ray total dose radiation effects on HfO₂-based ferroelectric thin-film memories with various configurations were investigated. Electrical characteristics such as I–V, P–V, C–V, ε_r–f, and fatigue properties of different capping electrodes, and diverse substrates of HfO₂-based ferroelectric thin films were quantified before and after the radiation. It was found from I–V characteristics of all configurations that I increases with the voltage in the range of 0 to the forward coercive voltage (V_c⁺), then it exhibited a reduction above V_c⁺, after a dose of 1 Mrad (Si), which indicated a weakened built-in electric field or a decreased depolarization field was induced by the ionizing radiation. The P–V and C–V of all the configurations displayed a decrease after the radiation tests due to an enhanced pinned effect of switchable domains. The attenuation in ε_r–f curves further certified the enhanced pinned effect of such configurations. A competitive relationship between the enhanced pinned effect and weakened built-in electric field was proposed to explain the performance evolution during the ionizing radiation. This work will be useful to better understand the radiation mechanism of HfO₂-based ferroelectric thin-film memories.