Effects of different metal electrodes on the ferroelectric properties of HZO thin films

Hafnium dioxide (HfO2)-based ferroelectric films are highly desirable due to their excellent compatibility with CMOS technology, good scalability, low operating voltage, and moderate polarization strength. However, the preparation of HfO2-based ferroelectric films inevitably introduces oxygen vacancies, which, under the influence of electric fields, redistribute and cause the awakening and fatigue phenomena of the films, ultimately resulting in the loss of ferroelectric performance. In this study, Hf0.5Zr0.5O2 (HZO) thin films were grown using atomic layer deposition (ALD) technology, and the influence of using different metal electrodes (W, Pt) as the top and bottom electrodes on the electrical properties of the HZO films was investigated. The leakage current of the W/HZO/W capacitor was the lowest, and the initial 2P(r) at 3 V was 41.4 mu C/cm(2), much higher than those of the W/HZO/Pt (15.7 mu C/cm(2)) and Pt/HZO/Pt (7.6 mu C/cm(2)) capacitors. As the number of electric field cycles gradually increased to 10(4), the 2P(r) values of the three capacitors changed. At this point, the 2P(r) value of the W/HZO/W capacitor was 53.9 mu C/cm(2), and the characteristic fatigue curve was flatter, indicating a weaker wake-up effect. These results indicate that the W electrode material can effectively promote the formation of the ferroelectric phase, reduce oxygen vacancies, and suppress the wake-up effect.