Atomistic modeling and simulation study for the ferroelectric-based electronic devices

Abstract

As the electronic devices have been scaled down to the nanoscale regime, the silicon-based devices have faced electrical and material limitations. To overcome these challenges, ferroelectric-based devices have attracted much attention to be a candidate for emerging electronic devices. Among the emerging ferroelectric-based devices, ferroelectric tunnel junctions (FTJs) are suggested as one of the emerging memory devices and can be utilized by various applications such as neuromorphic devices. After recent studies discovered the ferroelectric phase of HfO2, these outstanding properties of the ferroelectric HfO2 provide a breakthrough to commercialize FTJs. However, many studies have reported that the HfO2 based FTJs have shown poorer device performances compared to the perovskite oxide-based FTJs. Since HfO2-based FTJs still are at the early development stage, further works are required to improve the device performance. In this thesis, the device performances of the ferroelectric HfO2 tunnel junction are evaluated by the macroscopic model using Landau theory and quantum transport simulation. Also, to consider the atomistic effects which are not described by the macroscopic model, the first-principles density functional calculations are performed about the device characteristics of HfO2-based FTJs. Based on the simulation results, we suggest the design guideline to improve the performance of FTJs based on ferroelectric HfO2.