Reliability aspects of novel anti-ferroelectric non-volatile memories compared to hafnia based ferroelectric memories

摘要

The discovery of the ferroelectric (FE) properties within HfO₂ bridged the scaling gap between state-of-the-art technology nodes and ferroelectric memories. However, beside non-volatility, new memory concepts should ensure sufficient endurance and operation stability. Recently, it was shown that anti-ferroelectric (AFE) materials exhibit very stable and much higher endurance with respect to the FE counterparts. The latter show changes in the memory window (MW) followed by either hard breakdown or closure of MW much earlier than desired. Motivated by the remarkable cycling performance of the AFE, we analyze the physical mechanisms behind this high endurance strength. By characterizing the pure film properties in capacitor stacks and switching performance when integrated into devices, we compare the underlying mechanism and investigate the root cause for degradation of both FE and AFE memories. Combining the charge trapping and charge pumping tests as well as the leakage current spectroscopy with comprehensive modeling, we check the hypothesis that the lower energetic barrier to be overcome together with partial switching is responsible for the higher endurance and phase stability of the AFE with respect to the FE based memories.