Theoretical Study of Bilayer Composite Barrier Based Ferroelectric Tunnel Junction Memory

In this work, majority carrier tunneling current in Ferroelectric tunnel junction (FTJ) with bilayer composite barrier is simulated theoretically by using finite difference method and Wentzel-Kramers-Brillouin (WKB) method. The simulation results reveal that the metal/Al₂O₃/HZO/Si FTJ has a significant enhanced tunneling electroresistance (TER) effect as compared to traditional FTJ, and are also consistent with others' experimental results.

I. Introduction

Ferroelectric tunnel junction (FTJ) is a two-terminal device. Due to the distinctive advantages, such as high-density of data storage, nondestructive readout, low power consumption, FTJ has attracted great interest from many researchers for its great potential in next-generation memories [1]-[3], even as the synaptic devices for neurosynaptic computing [4]-[6]. Typically, FTJ has a thin ferroelectric (FE) layer which is served as tunneling barrier and sandwiched between two metallic electrodes, as shown in Fig. 1. Since the FE material has the characteristics of spontaneous polarization, after applying external electric field, the charge distribution at the interface between the electrode and the FE layer will change. As a result, the tunneling barrier height and resistance of FTJ can be modulated.