The enhanced electrode-dependent resistive random access memory based on BiFeO3

The electrode-dependent resistive random access memories (ReRAM) with aluminum, silver, platinum, and indium tin oxide (ITO) judiciously selected as a pair of electrodes, and the bismuth ferrite (BiFeO 3 or BFO) as the active dielectric layer, are fabricated for elaborate characterizations. The Ag/BFO/Pt and Ag/BFO/ITO ReRAMs have reflected excellent electrical properties, notably for the Ag/BFO/ITO combination. The Ag/BFO/ITO endures more than 1200 switching cycles and an excellent (> 10 2 ) on/off current or resistance ratio. The retention time in both high and low resistance states could reach 10 4 s and beyond. It has been found that the electrochemical metallization mechanism dominated by metal ion migration and the valence change mechanism dictated by oxygen vacancy conduction are inseparable from the establishment and destruction of the conductive filament. Moreover, a ReRAM with a dual dielectric layer of BFO/α-Fe 2 O 3 ) is also prepared for comparison. A special “two-step reset” phenomenon is observed which could be explained with filament theory.