Semiconductor device including fin field effect transistor and method of manufacturing the same

A semiconductor device, comprising:

• an active pattern protruding from a substrate;
• a plurality of gate structures each including a gate electrode and crossing the active pattern;
• and
• a source/drain region between the plurality of gate structures,
• wherein:
• the source/drain region includes:
• a first epitaxial layer in contact with a bottom surface and a sidewall of a recessed region in the active pattern,
• a high concentration doped layer in contact with an upper surface of a bottom end of the first epitaxial layer, and
• a second epitaxial layer covering the high concentration doped layer and the first epitaxial layer, and
• the high concentration doped layer has a first area in contact with the upper surface of the bottom of the first epitaxial layer and a second area in contact with a sidewall of the first epitaxial layer, the first area being wider than the second area.

A semiconductor device, comprising:

• an active pattern protruding from a substrate;
• a plurality of gate structures each including a gate electrode and crossing the active pattern;
• and
• a source/drain region between the plurality of gate structures,
• wherein the source/drain region includes:
• an implant doped layer below a recessed region in the active pattern,
• a first epitaxial layer in the recessed region, and
• a second epitaxial layer on the first epitaxial layer.