US Patent 11843053 Semiconductor devices

A semiconductor device is provided. The semiconductor comprises an active pattern including a lower pattern and a plurality of sheet patterns that are spaced apart from the lower pattern in a first direction, a source/drain pattern on the lower pattern and in contact with the plurality of sheet patterns, and a gate structure on opposing sides of the source/drain pattern in a second direction different from the first direction, the gate structure including a gate electrode on the plurality of sheet patterns, wherein the source/drain pattern includes an epitaxial region that comprises a semiconductor material and a cavity region that is inside the epitaxial region and that is surrounded by the semiconductor material.