Parametric FEM simulation of composite barrier FTJs under external bias at room temperature

TL;DR

This paper uses FEM simulations to analyze a composite barrier FTJ under bias at room temperature, predicting TER and current densities for various configurations to aid in device design.

Contribution

It introduces a parametric FEM-based simulation approach for composite barrier FTJs considering temperature effects and bias, providing insights into optimizing device performance.

Findings

FEM simulations reliably predict FTJ characteristics near 300 K.

Large TER values are achievable but with low ON-state currents.

Simulation results can guide FTJ material and structure optimization.

Abstract

A study on a parametrized model of a composite barrier FTJ (three-interface system, with a non-polar dielectric layer) under an external bias voltage and at room temperature, using FEM-based simulations, was performed. The approach involves the Thomas-Fermi model assuming incomplete screening of polarization charges for building the energy barrier profile, and numerically simulates the electron transport through the barrier by bias-voltage-dependent tunneling, using Tsu-Esaki formulation. That naturally include the temperature dependent contributions to the total current density. The TER coefficient and current densities are computed considering variation of a large set of parameters that describe the composite barrier FTJ system in realistic physical range of values with respect to a reference (prototypical) system. In this study, the parametric simulations were performed starting from selected data reported on the SRO/STO/BTO/SRO heterostructure. The most important results of our work can be stated as follows: i) The FEM simulations prove to be reliable approach when we are interested in the prediction of FTJ characteristics at temperatures close to 300 K, and ii) We show that several configurations with large TER values may be predicted, but at the expense of very low current densities in the ON state. We suggest that the results may be useful for assessing the FTJ performances at ambient temperature, as well as to design preoptimized FTJs by using different combinations of materials to comply with a set of properties of a specific model.