The present disclosure includes a high density resistive random access memory (RRAM) device, as well as methods of fabricating a high density RRAM device. One method of forming an RRAM device includes forming a resistive element having a metal-metal oxide interface. Forming the resistive element includes forming an insulative material over the first electrode, and forming a via in the insulative material. The via is conformally filled with a metal material, and the metal material is planarized to within the via. A portion of the metal material within the via is selectively treated to create a metal-metal oxide interface within the via. A second electrode is formed over the resistive element.