Theoretical Study of Carrier Transport in Metal–Ferroelectric–Insulator–Semiconductor Ferroelectric Tunnel Junction Memristor

Abstract

Ferroelectric tunnel junction (FTJ) based on the metal–ferroelectric–insulator–semiconductor (MFIS) stacks shows great potential in neuromorphic and in-memory computing. Tunneling current in the MFIS-FTJ can be calculated by the Wentzel–Kramers–Brillouin (WKB) method with the band profile solved from Poisson’s equation or by self-consistently solving Poisson’s equation and the drift-diffusion transport equations with a tunneling-induced carrier generation rate. The carrier redistribution in the semiconductor is neglected in the former method, which reduces the complexity and saves the computational cost but may or may not lead to significant errors. In this article, a comprehensive study of the two simulation methods mentioned above is performed to investigate their applicable conditions and balance the accuracy and computational cost. The current densities of the MFIS-FTJs with different material parameters, including the barrier width, barrier height, carrier mobility, and polarization charge density simulated by the two methods, are compared and analyzed. As the voltage drop across the semiconductor cannot be neglected, method II is required to take the carrier transport in the semiconductor into account and method I is not accurate; otherwise, method I is more suitable due to its low computational cost without loss of accuracy.