Temperature-Dependent Ferroelectric Behaviors of AlScN-Based Ferroelectric Capacitors with a Thin HfO2 Interlayer for Improved Endurance and Leakage Current

The ferroelectric switching behavior of a metal–ferroelectric AlScN–HfO2 interlayer–metal (MFIM) capacitor was investigated at variable temperatures and compared with an MFM capacitor. Although the MFIM capacitor demonstrated an inferior remnant polarization (2Pr value of 74 µC/cm2), it exhibited a reduced leakage current (×1/100) and higher breakdown field. The MFIM showed a stable change in 2Pr from room temperature to 200 °C and an enhanced endurance of ~104 cycles at 200 °C; moreover, the leakage current was less degraded after the cycling tests. Thus, the ferroelectric AlScN with a thin HfO2 interlayer can enhance the reliability of ferroelectric switching.