Semiconductor device

A semiconductor device comprising:

• a first conductive line on a semiconductor substrate;
• a second conductive line on the first conductive line;
• a third conductive line on the second conductive line;
• and
• a plurality of memory cell structures on the semiconductor substrate,
• the plurality of memory cell structures including a first memory cell structure and a second memory cell structure,
• the first memory cell structure being between the first conductive line and the second conductive line,
• the first memory cell structure including a first selector material pattern, a first information storage material pattern, and first electrode patterns overlapping each other in a vertical direction,
• the second memory cell structure being between the second conductive line and the third conductive line,
• the second memory cell structure including a second selector material pattern, a second information storage material pattern, and second electrode patterns overlapping each other in the vertical direction, and
• each of the first selector material pattern and the second selector material patterns including a first selector material layer having a first width and a second selector material layer having a second width narrower than the first width.

A semiconductor device comprising:

• a first conductive line;
• a second conductive line above the first conductive line;
• and
• a memory cell structure between the first conductive line and the second conductive line,
• the memory cell structure including an information storage material pattern and a selector material pattern connected to each other in series in a vertical direction,
• the selector material pattern including a first selector material layer having a first thickness and a second selector material layer having a second thickness,
• the first selector material layer including a first material, and the second selector material layer including a second material having a threshold voltage drift higher than a threshold voltage drift of the first material.