Memory device

A memory device comprising:

• a variable resistance layer;
• and
• a selection device layer electrically connected to the variable resistance layer and comprising a chalcogenide switching material having a composition according to chemical formula 3 below,
• GeXSiYAsZ(TebSe1-b)W (3)
• (where 0.05≦X≦0.1, 0.15≦Y≦0.25, 0.35≦Z≦0.45, 0.7≦b≦1.0, 0.3≦W≦0.4, and X+Y+Z+W=1).

A memory device comprising:

• a plurality of word lines extending along a first direction and spaced apart from each other along a second direction that is perpendicular to the first direction;
• a plurality of bit lines extending along the second direction and spaced apart from each other in the first direction, the plurality of bit lines being spaced apart from the plurality of word lines in a third direction that is perpendicular to both the first and second directions;
• a plurality of memory cells each one of which being arranged between corresponding cross points of the word and bit lines, each of said memory cells comprising;
• a lower electrode layer;
• a selection device layer;
• an intermediate electrode layer;
• a variable resistance layer;
• and
• an upper electrode,
• wherein the variable resistance layer includes a chalcogenide switching material having a composition that reduces leakage current.