Hf0.5Zr0.5O₂-Based Ferroelectric Field-Effect Transistors With HfO₂ Seed Layers for Radiation-Hard Nonvolatile Memory Applications

Hf _0.5 Zr _0.5 O ₂ (HZO)-based ferroelectric field-effect transistors (FeFETs) with HfO ₂ seed layer were investigated for radiation-hard nonvolatile memory applications. First, it was found that the HZO thin films grown on HfO ₂ seed layer showed improved crystallinity and ferroelectricity compared with those directly grown on SiO ₂ thin film, leading to a larger memory window (MW), better endurance, and retention properties of the HZO-based FeFETs with HfO ₂ seed layers. Moreover, after 1 Mrad(Si) ⁶⁰ Co γ-ray irradiation, the memory properties of the HZO-based FeFETs with HfO ₂ seed layer were also better than those without the HfO ₂ seed layer. Especially, the HZO-based FeFETs with an HfO ₂ seed layer have a larger remaining MW (0.66 V) than that (0.29 V) of the FeFETs without an HfO ₂ seed layer after 1×10 ⁴ program/erase cycle. This work represents a first attempt to realize the high performances of radiation-hard HfO ₂ -based FeFETs.