Self-Formation of Sub-10-nm Nanogaps by Silicidation for Resistive Switch in Air

TL;DR

This paper presents a simple, scalable method for fabricating sub-10-nm nanogaps via silicidation, enabling high-performance resistive switches with large on/off ratios suitable for complex circuits.

Contribution

The authors introduce a novel silicidation-based process for creating nanogaps that are precisely controlled by metal layer thickness, allowing for scalable production of resistive switching devices.

Findings

Nanogaps exhibit up to 10^3 on/off conductance ratios.

Forming voltages depend on nanogap size, while switching voltages do not.

Method allows for symmetric, asymmetric, and multiple nanogaps in a single step.

Abstract

We developed a simple and reliable method for the fabrication of sub-10-nm wide nanogaps. The self-formed nanogap is based on the stoichiometric solid-state reaction between metal and Si atoms during silicidation process. The nanogap width is deter- mined by the metal layer thickness. Our proposed method produces nanogaps either symmetric or asymmetric electrodes, as well as, multiple nanogaps within one unique process step for application to complex circuits. Therefore, this method provides high throughput and it is suitable for large-scale production. To demonstrate the feasibil- ity of the proposed fabrication method, nanogap resistive switches have been built and characterized. They exhibit a pronounced hysteresis with up to 103 on/off conductance ratios in air. Our results indicate that the voltages for initially electroforming the de- vice to the switch state are determinated by the nanogap sizes. However, the set and reset voltages of the device do not strongly dependent on the nanogap widths. These phenomena could be helpful to understand how the resistive switching is established.