Semiconductor devices

A semiconductor device comprising:

• a substrate;
• a plurality of semiconductor patterns extending in a first horizontal direction, above the substrate, and spaced apart from one another in a second horizontal direction and a vertical direction, which intersect the first horizontal direction, the plurality of semiconductor patterns each comprising a first end and a second end;
• a bit line connected to the first ends of the plurality of semiconductor patterns and extending in the vertical direction;
• a plurality of word lines extending in the second horizontal direction, above the plurality of semiconductor patterns;
• a plurality of cell capacitors respectively connected to the second ends of the plurality of semiconductor patterns;
• a plate electrode connected to the plurality of cell capacitors and extending in the vertical direction;
• and
• a first lower separation structure partially passing through the substrate in the vertical direction and located between the substrate and the plate electrode, the first lower separation structure extending above the substrate to cover at least one semiconductor pattern.

A semiconductor device comprising:

• a substrate;
• a plurality of semiconductor patterns extending in a first horizontal direction, above the substrate, and spaced apart from one another in a second horizontal direction and a vertical direction, which intersect the first horizontal direction, the plurality of semiconductor patterns each comprising a first end and a second end;
• a bit line connected to the first ends of the plurality of semiconductor patterns and extending in the vertical direction;
• a plurality of word lines respectively surrounding the plurality of semiconductor patterns and extending in the second horizontal direction;
• a plurality of cell capacitors respectively connected to the second ends of the plurality of semiconductor patterns;
• a plate electrode connected to the plurality of cell capacitors and extending in the vertical direction;
• and
• a lower separation structure partially passing through the substrate in the vertical direction and located at one or more positions among a position between the substrate and the bit line and a position between the substrate and the plate electrode,
• wherein the lower separation structure comprises:
• a first vertical section extending in the vertical direction, above the substrate, to cover at least one semiconductor pattern;
• and
• a second vertical section extending in the vertical direction and partially passing through the substrate, and
• wherein a thickness of the second vertical section of the lower separation structure is less than a thickness of the first vertical section of the lower separation structure.