Resistive Switching Behaviors of Al-Te Alloy Thin Films Formed by Thermal-Intermixing of Al/Te Bilayer

Abstract

As the demand for high-capacity, high-speed, and power-efficient memory system as a logic processing assistant and also a data storage continues to grow, the 3D X-Point is positioned to play a significant role in the upcoming semiconductor technology. However, a significant limitation of 3D X-Point structure is its susceptibility to sneak path currents in multi-layer crossbar arrays, which can result in unintended data access and interference. Given these challenges, some chalcogenide materials, noted for their unique electrical switching behavior known as ovonic threshold switching, are getting more and more attention as promising candidates for constructing the selector devices to resolve the sneak path issue. In this study, we show that Al-Te chalcogenide alloy thin films exhibit resistive switching behaviors, both threshold switching and memory switching. The Al-Te alloy films are prepared by first growing a bilayer stack of Al and Te thin films with thermal evaporation and then annealing the stack to form an alloy driven by atomic intermixing. One benefit of starting with the stack structure is that it becomes possible to control the compositional ratio of the formed alloy somewhat precisely by varying the thicknesses of Al and Te layers. As the Al proportion in the alloy film increases, the memory switching is found to become more prominent compared to the threshold switching. In the case of memory switching, the maximum switching ratio is extracted to be ~300:1. Meanwhile, it reaches up to ~40:1 for the threshold switching. Our findings are expected to contribute not only to optimizing the fabrication processes for achieving the stable memory and threshold switching but also to advancing the understanding about the fundamental physical mechanisms of both switching behaviors.