Structural and Electrical Behavior of Swift Heavy Ion Irradiated Hafnium Oxide Polymorphs in Ferroelectric and Resistive Memories

Hafnium oxide (HfO2) exhibits multiple polymorphs, each with distinct properties and is a promising material for non-volatile memory technologies in radiation-harsh environments. To gain a comprehensive understanding of the radiation response of HfO2-based memory devices requires detailed investigations of ion beam-induced phase changes as well as, recrystallization processes and amorphization in the different HfO2 polymorphs. This study explores the effects of swift heavy-ion irradiation on HfO2 in resistive random-access memories (RRAM) and metal-insulator-metal (MFM) capacitors, using 1.635 GeV Au ions, to simulate an extreme damage scenario, and 183 MeV Ca ions, which are more relevant to space missions due to their lower mass. The exposure of RRAM layers and MFM capacitors to Ca ions has a negligible effect on the crystallinity of HfO2 with little to no impact on the switching behavior of the capacitors, indicating that the energy loss threshold for inducing phase transitions is not exceeded. Comparing La-doped HfO2 (HLO) and hafnium zirconium oxide (HZO) MFM capacitors reveals that HZO exhibits remarkable resilience against Au ion irradiation up to fluences of 7 × 1012 ions/cm2, without any reduction in saturation polarization and that the ferroelectric properties of HLO and HZO can be restored and even enhanced through post-irradiation cycling.