Switching element, switching element array, and resistive random access memory including switching element, and methods of manufacturing the same

A method of manufacturing a switching element, the method comprising:

• sequentially forming a first electrode layer and an insulation material layer over a substrate;
• forming a doping mask pattern over the insulation material layer, the doping mask pattern exposing a portion of the insulation material layer;
• injecting dopants into the exposed portion of the insulation material layer;
• removing the doping mask pattern;
• forming a second electrode layer over the insulation material layer;
• and
• forming one or more pillar-shaped structures, each of which includes a second electrode, an insulation layer, and a first electrode, by respectively patterning the second electrode layer, the insulation material layer, and the first electrode layer,
• wherein each of the one or more pillar-shaped structures includes, in the insulation layer, a part of the exposed portion of the insulation material layer that is doped with the dopants, and
• wherein a threshold switching operation is performed in a region of the insulation layer that is doped with the dopants.