Polarization enhancement in Hf0.5Zr0.5O2 capacitors induced by oxygen vacancies at elevated temperatures

This paper discusses a mechanism and method for polarization enhancement in fabricated Hf0.5Zr0.5O2 (HZO) capacitors. The proposed reawakening voltage operation method (RVOM) to HZO films at elevated temperatures increases the transient switching current and polarization. The change in conduction mechanisms for the HZO capacitor current after RVOM can be observed by fitting leakage current curves. The generation of oxygen vacancies (V-O) by RVOM causes a rapid increase in the leakage current and a gradual degradation in the breakdown voltages of HZO capacitors. As a result, while an appropriate amount of V-O generation improves the polarization, an excess will damage the reliability of HZO films. Furthermore, the augmentation of polarization does not disappear after the cooling process, which indicates that the V-O as induced by RVOM does not attenuate as the temperature decreases. Our approach and the experimental results have generated ideas on how to improve the polarization of HZO films.