Effects of electrode materials on bipolar and unipolar switching in NiO resistive switching device

NiO resistive switching access memory (RRAM) devices were grown by DC-sputtering with two different top electrodes. When selected Au as the top electrode, the unipolar switching were observed in both positive and negative bias voltage range. However, when changed the top electrode to Co, the bipolar and unipolar resistive switching in negative bias voltage were achieved. Comparing these two top electrodes, the observations provide evidence that the migration of Co cations in insulation layer result in bipolar switching and the reason was attributed to electrochemical metallization memory (ECM) effect. Furthermore, it also confirmed that bipolar resistive switching tended to form in the electrodes with high activity. (C) 2014 Elsevier B.V. All rights reserved.