Forming-Free and Non-linear Resistive Switching in Bilayer HfOx/TaOx Memory Devices by Interface-Induced Internal Resistance

Abstract

Abstract: Resistive switching memory devices with tantalum oxide ((Formula presented.)) and hafnium oxide ((Formula presented.)) mono- and bilayers were fabricated using atomic layer deposition. The bilayer devices with Ti and TiN electrodes show non-linear switching characteristics, and can operate without requiring an initial electroforming step. The insertion of the (Formula presented.) layer induces the switching behaviour on single layer (Formula presented.) that shows Zener diode-like characteristics, with conductivity depending on the top electrode metal. The electronic conductivity mechanism study shows Schottky emission at low voltage regime followed by tunneling at higher applied bias, both indicating interface-dominated conduction. The switching mechanism study is supported by X-ray photoelectron spectroscopy characterization of the films that show a formation of (Formula presented.) and (Formula presented.) species at the oxide-electrode interface. This interfacial layer serves as a high resistivity barrier layer enabling the homogeneous resistive switching behavior. Graphical Abstract: (Figure presented.)