Improved Memory Density and Endurance by a Novel 1T3C FeFET for BEOL Multi-level Cell Memory

We report a novel FeFET based on one-transistor-three-capacitors (1T3C) structure to address the trade-off between the memory density and endurance in multi-level cell (MLC) memory. The multi-level states are stored as the different configurations of polarization among the three ferroelectric capacitors, thus enhancing the memory density without degrading the endurance. The 1T3C FeFET employs oxide semiconductor channel of InZnO (IZO) for back-end-of-line (BEOL) compatibility, and shows high performance including four-level threshold voltage (V <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">th</inf> ) states, Iₒₙ/ Ioff > 10, memory window (MW) of 1.8 V, endurance up to 4 10 and retention of > 10 years.