Electrical characteristics investigation of ferroelectric memories using stacked and mixed hafnium zirconium oxides

In this work, we investigate ferroelectric characteristics of hafnium zirconium oxide (HfZrO) metal-ferroelectric-metal (MFM) devices with mixed and stacked film structure. The experimental results reveal that the stacked HfZrO MFM device has a lower dynamic leakage and stronger ferroelectric polarization value of approximately 27.3 μC/cm², which is much higher than 17.5 μC/cm² measured from mixed HfZrO MFM device. From endurance cycling test, we also confirm that the stacked HfZrO MFM capacitor with a remote nitrogen plasma treatment featuring a large initial hysteresis window can achieve a stable operation up to 10⁸ cycles at an operating voltage of 2.5 V, which is even longer than that of mixed HfZrO MFM capacitor by one order of magnitude. Therefore, the stacked MFM structure with proper interface engineering provides a promising approach for the process integration of ferroelectric memory under the comprehensive consideration of device performance and endurance.