Anti-ferroelectric-like ZrO2 non-volatile memory: Inducing non-volatility within state-of-the-art DRAM

摘要

Even though the discovery of ferroelectricity in HfO₂ enabled further scaling of ferroelectric (FE) memories, these memories suffer from limited endurance. Recently, we showed how the non-volatility can be induced within the state-of-the-art DRAM capacitor stacks. By using an asymmetric stack, comprising electrodes with different workfunction values an internal bias field can be used to make anti-ferroelectric (AFE) ZrO₂, which is used as a dielectric in DRAM, non-volatile (NV). In this way, an excellent endurance compared to HfO₂ based ferroelectric memories is achieved. In this work we provide an overview of theoretical considerations and different methods which can be utilized for the introduction of the internal bias field required for centering of one of the AFE hysteresis loops. Furthermore, memory performance and design limitations due to stack asymmetry are discussed. In addition, an operation scheme for this novel AFE NV memory is suggested.