BEOL-Compatible 5.6 nm Ultrathin HZO With Molybdenum Nitride Electrode and IN2O3 Channel Devices for Enhanced Ferroelectricity and Reliability

In this letter, we have successfully fabricated a metal-ferroelectricity-metal (MFM) capacitor of an ultrathin 5.6 nm HZO and ultrathin In₂O₃ back gate devices in a back-end-of-line (BEOL) compatible process. By proposing a novel atomic layer deposition (ALD) scheme and an alternative bottom electrode treatment, the MoN-HZO sample shows an average 2Pr value of 64 μC/cm² (with a standard deviation of 0.52) and high endurance (△2Pr/2Pr_pristine ≈2% from pristine to 10¹⁰ cycles). The MoN–HZO stack integrated with an ultrathin In₂O₃ back gate exhibits a memory window (MW) greater than 2.5 V and excellent endurance and data retention characteristics. With a maximum process temperature of 400°C, our approach meets the stringent requirements for Back-End-of-Line (BEOL) integration.