Highly Enhanced Polarization Switching Speed in HfO₂‐based Ferroelectric Thin Films via a Composition Gradient Strategy

Abstract The next‐generation semiconductor memories are essentially required for the advancements in modern electronic devices. Ferroelectric memories by HfO₂‐based ferroelectric thin films (FE‐HfO₂) have opened promising directions in recent years. Nevertheless, improving the polarization switching speed of FE‐HfO₂ remains a critical task. In this study, it is demonstrated that the composition‐graded Hf_1‐xZr_xO₂ (HZO) ferroelectric thin film has more than two times faster polarization switching speed than the conventional composition‐uniform one. Meanwhile, it has excellent ferroelectricity and improved endurance characteristics. It is also discovered that when the HZO thin film has a gradient composition, the polarization‐switching dynamics shifts from the nucleation‐limited‐switching mechanism to the domain‐wall growth mechanism. Moreover, the transition of switching dynamics is responsible for the faster speed and better endurance of the composition‐graded HZO thin film. These findings not only reveal the physical mechanisms of this material system but also provide a new strategy for memory devices having faster speed and higher endurance.