Cuz+ ion migration and filament formation. (a) HRTEM image of an Al/Cu/Ge0.2Se0.8/W resistive memory device after 6 × 103 P/E cycles and the device kept in SET condition. (b) The diameter of the Cu filament is approximately 30 nm. (c) Amorphous Ge0.2Se0.8 film is observed at the without-filament region by FFT. (d) FFT in Cu electrode. (e) to (f) Crystalline Cu filament is observed. (g) EDX analysis at the points indicated in (b). The numbers (1), (2), and (3) indicated in (b) correspond to the EDX analysis positions.
Rahaman et al. Nanoscale Research Letters 2012 7:614 doi:10.1186/1556-276X-7-614