Size-Dependent Drift of Resistance Due to Surface Defect Relaxation in Conductive-Bridge Memory

Conductive-bridge random access memory (CBRAM) devices have shown low-power programming, fast switching, and good device scalability. In particular, the large resistance window and good control of the conductive filament (CF) size may allow for efficient multilevel-cell (MLC) operation. Toward this aim, the structural stability of the CF must be demonstrated. This letter addresses the stability of the set states in CBRAM. We evidence a size-dependent drift of the CF resistance, which is interpreted by surface relaxation due to defect rearrangement. An analytical model is developed, describing the size-dependent drift in terms of partial and full depletion of the CF by the surface defect.