Highly Stable Forming-Free Bipolar Resistive Switching in Cu Layer Stacked Amorphous Carbon Oxide: Transition between C-C Bonding Complexes

Abstract

Recent advances in resistive switching devices have garnered a considerable amount of interest as an alternative option for next-generation nonvolatile memories due to their distinct advantages of ultralow power consumption, fast operation, and outstanding scaling potential. Among the recently considered active media, amorphous carbon oxide (alpha-C:O-x) shows promise in terms of device performance, essentially due to the transition between carbon sp(2)-sp(3) complex under bias. However, widespread utilization of this media still remains a challenge due to its undesirable high forming voltage and insufficient stability issues. Here, a simple approach to stack a suitable Cu layer at the alpha-C:O-x layer/W interface of simple Pt/alpha-C:O/W frames is introduced to engineer resistive switching characteristics. Precise control of a stacked Cu layer (2.5 nm thick) identifies numerous benefits of forming-free characteristics, reliable switching time, and appreciably stable features compared with those of single alpha-C:O-x active medium. The possible principle underlying the experimental findings is described based on the oxygen ion drift-driven transition between sp(2) and sp(3) bonds at the intermixed regions of alpha-C:O-x/Cu interfaces under bias, which are systematically confirmed by structural observations.