Radiation-Resilient Amorphous Indium Oxide FEFETs for Embedded Nonvolatile Memory

We report the first-ever study on the radiation resilience of a back-end-of-line (BEOL) compatible W-doped Indium Oxide (IWO) ferroelectric field-effect transistor (FEFET) under neutron irradiation. The findings demonstrate remarkable resilience of both Hf<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</inf>Zr<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.5</inf>O<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>(HZO) ferroelectric capacitors (FECAPs) and IWO FEFETs to neutron irradiation. Subjected to neutron irradiation at fluences up to 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">15</sup> n/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, HZO FECAPs maintain stable remnant polarization (2P<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</inf>) and coercive voltage (2V<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</inf>) up to 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sup> cycles without any breakdown. The IWO FEFETs show robust switching performance and exhibit minimal degradation in memory window (MW) and read current window (CW). Importantly, the retention and endurance performance remain stable after neutron radiation exposure, without significant failure. Destiny simulations were performed to assess the impact of radiation on the system-level performance of an 8 MB 1T-1FEFET-based embedded RAM at the 32 nm node. The results showed negligible effects on read latency and only a minor 0.36% increase in dynamic read energy at a neutron fluence of 10y15 n/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. The combination of high performance, non-volatility, and radiation hardness makes IWO FEFETs a promising candidate for high-density, persistent memory applications in radiation-rich environments.