Semiconductor device including vertical channel structure

A semiconductor device comprising:

• a channel structure having a lower surface and an upper surface opposite the lower surface;
• a bit line connected to the lower surface of the channel structure;
• a contact pattern connected to the upper surface of the channel structure;
• a gate electrode facing a side surface of the channel structure;
• and
• a gate dielectric layer disposed between the channel structure and the gate electrode,
• wherein the channel structure includes a plurality of oxide semiconductor layers, and
• wherein the plurality of oxide semiconductor layers include a first oxide semiconductor layer and a second oxide semiconductor layer different from the first oxide semiconductor layer.

A semiconductor device comprising:

• a channel structure;
• a bit line connected to a first region of the channel structure;
• a data storage structure connected to a second region of the channel structure;
• a gate electrode facing a third region of the channel structure;
• and
• a gate dielectric layer disposed between the channel structure and the gate electrode,
• wherein the channel structure includes:
• a first portion extending in a first direction;
• and
• a second portion extending in a second direction from one side of the first portion,
• wherein the second direction intersects the first direction,
• wherein the gate electrode overlaps the first portion of the channel structure in the second direction,
• wherein the channel structure includes a plurality of oxide semiconductor layers, and
• wherein the plurality of oxide semiconductor layers include a first oxide semiconductor layer and a second oxide semiconductor layer different from the first oxide semiconductor layer.