Bi‐Stable Resistance Generation Mechanism for Oxygenated Amorphous Carbon‐Based Resistive Random‐Access Memory

• Published in: Advanced electronic materials Vol. 8; no. 5
• Main Authors: Jin, Soo‐Min, Kim, Hea‐Jee, Woo, Dae‐Seong, Jung, Sung‐Mok, Kim, Dong‐Eon, Shim, Tae‐Hun, Park, Jea‐Gun
• Format: Journal Article
• Language: English
• Published: 01.05.2022
• Subjects: 3D cross‐point nonvolatile memories; bi‐stable resistances; C C sp 2 covalent bonds; C C sp 3 covalent bonds; oxygenated amorphous carbon; resistive random‐access memories
• ISSN: 2199-160X; 2199-160X
• DOI: 10.1002/aelm.202101083

The oxygenated amorphous carbon (α‐COx)‐based resistive random‐access memory (ReRAM) generates a bi‐stable resistance via electroforming or the rupture of the conductive CC sp2 covalent bond filaments in the α‐COx resistive layer, which can be determined by the dependency of the intensity distribution of the oxygen ion (O2−), for the 3D cross‐point nonvolatile memory as the new memory hierarchical structure for an artificial neural network. The conductive CC sp2 and insulating CC sp3 covalent bonds are formed near the top of the resistive layer by drifting and diffusing O2− toward the bottom and top parts of the layer in the set and reset processes, respectively. The reset process has a different bi‐stable resistance generation mechanism from binary metal oxide‐based ReRAM and conductive bridge random‐access memory. The conductive CC sp2 covalent bond intensity in the α‐COx resistive layer affects the forming voltage and the write and erase endurance cycle of the α‐COx‐based ReRAM cells. The result shows that a lower proportion of conductive CC sp2 covalent bond leads to longer write and erase endurance cycles. The bi‐stable resistance states of the oxygenated amorphous carbon‐based resistive‐random‐access‐memory cell are originated via electroforming or the rupture of the conductive CC sp2 filaments in the resistive layer near top electrode. The transition between electroforming and the rupture of the conductive CC sp2 filaments is determined by the oxygen ion diffusion and drift direction depending on set or reset.