Enhancing ferroelectric performance in hafnia-based MFIS capacitor through interface passivation and bulk doping

In recent times, there has been a notable surge of interests in hafnia (HfO₂)-based ferroelectrics, primarily due to their remarkable ferroelectric properties employed in ultra-thin configurations, alongside their compatibility with the conventional CMOS manufacturing process. In order to harness the full potential of HfO₂-based films for high-performance non-volatile memory applications, it is imperative to enhance their ferroelectric characteristics and durability. This study introduces a straightforward approach aimed at augmenting the ferroelectric performance of Hf_xZr_1-xO₂(HZO) films deposited on silicon (Si) substrates through the engineering of oxygen vacancies (V_O). The results of this endeavor demonstrate a significant enhancement in ferroelectric performance, characterized by a 2Pr value of 47μC cm^-2and impressive endurance, enduring up to 10⁸cycles under an 8 MV cm^-1electric field without the need of a wake-up process. This marked improvement can be attributed to a dual-pronged approach, involving the incorporation of an Al₂O₃interlayer and the introduction of Al atoms into the HZO film. The Al₂O₃interlayer primarily serves to mitigate the presence of oxygen vacancies at the interface, while the introduction of Al dopants elevates the concentration of oxygen vacancies within the bulk material. This modulation of oxygen vacancy concentration proves instrumental in facilitating the formation of a ferroelectric o-III phase within the HZO-based films, thereby further augmenting their ferroelectric performance. This innovative and effective strategy offers an alternative avenue for enhancing the ferroelectric properties of materials characterized by a fluorite crystal structure.