Cause and prevention of moisture-induced degradation of resistance random access memory nanodevices

摘要

Dielectric thin films in nanodevices may absorb moisture, leading to physical changes and property/performance degradation, such as altered data storage and readout in resistance random access memory. Here we demonstrate using a nanometallic memory that such degradation proceeds via nanoporosity, which facilitates water wetting in otherwise nonwetting dielectrics. Electric degradation only occurs when the device is in the charge-storage state, which provides a nanoscale dielectrophoretic force directing H_2O to internal field centers (sites of trapped charge) to enable bond rupture and charged hydroxyl formation. While these processes are dramatically enhanced by an external DC or AC field and electron-donating electrodes, they can be completely prevented by eliminating nanoporosity, depositing a barrier layer, or using an oxidation-resistant electrode. These findings provide insight for understanding high-performance memory and field-assisted degradation of nanodevices.