Semiconductor device

A semiconductor device, comprising:

• a pair of first semiconductor patterns on a substrate, the pair of first semiconductor patterns spaced apart from each other in a first direction parallel to a top surface of the substrate;
• second semiconductor patterns between the pair of first semiconductor patterns and connected to the pair of first semiconductor patterns, the second semiconductor patterns spaced apart from each other in a second direction perpendicular to the top surface of the substrate;
• and
• a gate structure between the pair of first semiconductor patterns and covering the second semiconductor patterns, wherein each of the second semiconductor patterns includes a central portion between end portions in the first direction, the end portions of the second semiconductor patterns including a same impurity as the pair of first semiconductor patterns, and the central portions of the second semiconductor patterns having different lengths and different thicknesses from each other.

A semiconductor device, comprising:

• a plurality of patterns stacked on a substrate;
• and
• a plurality of gate electrodes on respective ones of the patterns,
• wherein the patterns include channels and wherein lengths of the channels or gate electrodes progressively change to offset a progressive change in thicknesses of the channels or gate electrodes in a predetermined direction.