Ionizing Radiation Effect on Memory Characteristics for HfO2-Based Ferroelectric Field-Effect Transistors

HfO ₂ -based ferroelectric field-effect transistors (FeFET) on Si were employed as the platform to investigate the impact of ⁶⁰ Co γ-rays radiation on memory characteristics. For pristine state, the memory window by ±4 V sweeping for non-irradiated devices is 1.48 V which does not degrade with 300-krad and 10-Mrad radiation dose even though the remnant polarization (P _r ) decreases due to radiation-induced oxygen vacancies (Vo) and lattice distortion in the ferroelectric material HfZrOx (HZO). With the radiation dose level, the devices still hold the current ratio between “1” and “0” state of 2.2 × 10 ³ by extrapolating to 10 years at 25 °C, which is comparable to that of non-irradiated devices. The most adverse effect of radiation is the deteriorated endurance caused by the increased number of Vo during cycling test (+5.5 V, -5 V/10 μs) as evidenced by memory window of 0.52 V at 10 ⁶ cycles for devices with 300-krad radiation dose. Furthermore, robust HZO and SiO _x interacial layer against radiation is required to suppress the bond break so that the reliability can be improved.