Semiconductor device having a transistor structure and a method of manufacturing the semiconductor device

A semiconductor device having a transistor structure, wherein the transistor structure comprises:

• fin active regions vertically protruding from a substrate and extending parallel with each other in a first horizontal direction;
• isolation regions between the fin active regions to define the fin active regions;
• and
• gate structures extending in parallel with each other to cross the fin active regions and the isolation regions in a second horizontal direction,
• wherein each of the gate structures includes:
• an upper gate structure having a line shape disposed over the fin active regions and extending in the second horizontal direction;
• and
• lower gate structures disposed between the fin active regions,
• wherein each of the lower gate structures has a first horizontal width in the first horizontal direction,
• wherein each of the upper gate structures has a second horizontal width in the first horizontal direction, and
• wherein the first horizontal width is less than the second horizontal width.

A method of manufacturing a semiconductor device having a transistor structure, the method comprises:

• recessing some portions of a substrate to form trenches;
• forming isolation regions by filling the trenches with insulating materials, wherein the isolation regions define fin active regions extending in parallel with each other in the first horizontal direction;
• recessing the isolation regions between the fin active regions to form grooves exposing some portions of side surfaces of the fin active regions;
• and
• forming gate structures extending in parallel with each other to cross the fin active regions and the isolation regions in the second horizontal direction,
• wherein each of the gate structures comprises:
• an upper gate structure disposed over surfaces of the fin active regions and extending in the second horizontal direction;
• and
• lower gate structures formed in the grooves,
• wherein a horizontal width of each of the lower gate structures is less than a horizontal width of the upper gate structure in the first horizontal direction.

A transistor structure for a semiconductor device, the transistor structure comprising:

• a plurality of spaced apart fin active regions vertically protruding above a top surface of a substrate, arranged parallel to each other at regular intervals, wherein each fin active region has a dam shape with a wider base and narrower top,
• a plurality of gate structures crossing over the fin active regions,
• wherein each of the gate structures includes an upper gate structure disposed over the fin active region and a lower gate structure disposed on both sides of a corresponding fin active region,
• wherein:
• a width of the lower gate structure in the first horizontal direction is less than a width of the upper gate structure.