The role of oxygen vacancies on switching characteristics of TiO_x resistive memories

Using oxygen vacancy rich (VO-rich) TiO_x dielectric with high work function Ni electrode, large resistance window of > 10x and narrow current distribution were realized in the Ni/VO-rich TiO_x/TaN resistive random access memory (RRAM) device. It can be ascribed to the formation and rupture of conducting filaments by the percolation of VOs and Ti interstitials. Moreover, the effects of annealing treatment and top electrode on resistive switching properties were investigated. The device with VO-deficient TiO_x after annealing reduces the defects and exhibits small window and low switching currents. The device with low work function Ti top electrode provides low barrier to increase reset currents and the randomly distributed filamentary paths forms near the Ti causes wide current distribution.