Post-Annealing Effect on Resistive Switching Performance of a Ta/Mn2O3/Pt/Ti Stacked Device

A comparative study of Ta/Mn2O3/Pt/Ti stacked capacitor-like resistive switching (RS) devices was performed as a function of the post-annealing process conditions. Compared to as-fabricated RS devices, the post-annealed ones showed higher switching endurance (approximate to 10(9) RS cycles), good retention characteristics, and narrow operational voltage distribution. To elucidate the microscopic origins of the superior RS performance, various analyses are conducted; and it is revealed that structural and chemical composition changes in post-annealed RS devices can improve the RS performance. In the case of post-annealed samples, unintentionally diffused Ti is observed between the manganese oxide layer and the Pt bottom electrode. Because of the metallic property of diffused Ti, it can be a good electron donor and a center of RS during the formation of a conducting filament (CF) in manganese oxide for nearly uniform RS operation. The highly reliable endurance characteristic is attributed to a TaOx layer between the Ta top electrode and the manganese oxide. The non-stoichiometric TaOx layer that is formed during the post-annealing process can play the role of an effective oxygen reservoir, and approximate to 10(4) times more RS endurance cycles could be achieved compared to the as-fabricated RS device.