Scaling the CBRAM Switching Layer Diameter to 30 nm Improves Cycling Endurance

Control of cation injection into the switching layer of conductive-bridge random access memory (CBRAM) during switching is a critical factor for CBRAM reliability. Although extrinsic approaches such as the insertion of a transistor in series have proven effective, solutions intrinsic to the CBRAM itself, which are desired for high density cross-point or 3-D vertical memory arrays, are quite limited. In this letter, we show the significant improvement of cycling endurance for Cu-based CBRAM by scaling the switching layer area down to 30 nm in diameter. Further study suggests that the injection of excessive Cu ions into the switching layer is suppressed owing to spatial limitation during the formation of the conductive filament. These results indicate that the area scaling of the switching layer is an effective solution for achieving highly reliable CBRAM devices.