Vertical array of resistive switching devices having restricted filament regions and tunable top electrode volume

A vertical resistive device comprising:

• a horizontal plate comprising a conductive electrode region and a filament region;
• an opening extending through the filament region and defined by sidewalls of the filament region, wherein the filament region is positioned outside of the opening;
• and
• a conductive pillar positioned within the opening and communicatively coupled to the filament region;
• wherein the conductive pillar comprises a reactive electrode and a metal fill material;
• wherein the reactive electrode comprises:
• a bottom layer comprising titanium nitride (TiN) and having a thickness dimension from about 0.3 nm to about 3.0 nm;
• an intermediate layer comprising (M)AlC, where M is a transition metal selected from the group consisting of titanium (Ti), tantalum (Ta), and Niobium (Nb), wherein the intermediate layer comprises a thickness dimension from about 1 nm to about 10 nm;
• and
• a top layer comprising TiN and having a thickness dimension from about 1 nm to about 3 nm.

A method of forming a vertical resistive device, the method comprising:

• forming a stack comprising:
• a horizontal plate comprising a conductive electrode region and a filament region;
• an opening extending through the filament region and defined by sidewalls of the filament region, wherein the filament region is positioned outside of the opening;
• and
• a conductive pillar positioned within the opening and communicatively coupled to the filament region;
• wherein the conductive electrode region functions as a bottom electrode of a resistive switching device (RSD);
• wherein the filament region functions as an insulator region of the RSD;
• wherein the conductive pillar functions as a top electrode of the RSD;
• and
• controlling an oxygen vacancy concentration of the RSD by:
• controlling a thickness of a plurality of metals forming the top electrode;
• and
• controlling a percentage of one of the plurality of metals forming the top electrode.