Cyclic Plasma Treatment for Enhancing the Synaptic Performance of Bulk-Conductive Resistive Switching Memory

Plasma-based interfacial treatments have previously enhanced the performance of filamentary-conductive resistive switching memories (RSMs). Still, strategies for improving bulk-conductive RSMs remain limited. While the bulk-conductive RSM has been explored for neuromorphic computing due to its gradual and analog switching behavior that allows for linear conductance change, it suffers from endurance degradation under repeated cycling. This study introduces a cyclic plasma treatment (CPT) method, employing periodic Ar plasma exposure during the deposition of an HfO₂ switching layer via plasma-enhanced atomic layer deposition. The performances of W/HfO₂/TiN (WHT) bulk-conductive RSMs with and without CPT were compared to evaluate the influence of CPT. The CPT effectively decreased switching degradation by introducing additional oxygen vacancies into the switching layer, compensating for the loss of trap sites caused by oxygen recombination. Device endurance improved from 10⁴ to 10⁶ cycles, and cycle-to-cycle and device-to-device variations improved by 77% and 78%, respectively. The MNIST classification simulation was performed by using cyclic plasma-treated WHT RSMs, achieving a high accuracy of 91.4%. This result demonstrates CPT as a promising solution for enhancing bulk-conductive resistive switching in neuromorphic computing.