Semiconductor device having asymmetrical source/drain

A method of forming a semiconductor device, comprising:

• forming active fins, wherein each of the active fins comprises a first fin area and a second fin area;
• forming an isolation layer on side surfaces of lower portions of the active fins;
• forming a sacrificial gate on the first fin areas of the active fins and the isolation layer;
• forming recessed second fin areas by etching the second fin areas, after forming the sacrificial gate;
• forming a source/drain on the recessed second fin areas;
• forming an interlayer insulating layer on the source/drain and the isolation layer;
• forming a gate trench by removing the sacrificial gate, after forming the interlayer insulating layer;
• and
• forming a gate structure in the gate trench,
• wherein the source/drain contacts at least two of the active fins at a same time and has a merged double-diamond shape,
• wherein the source/drain comprises first crystal growth portions that contact upper surfaces of the at least two of the recessed second fin areas, second crystal growth portions that share at least one plane with the first crystal growth portions and that contact side surfaces of the at least two of the recessed second fin areas, and a third crystal growth portion formed to merge adjacent edges of the first crystal growth portions.

A method of forming a semiconductor device, comprising:

• forming an active fin protruding from a substrate, wherein the active fin comprises a first fin area and a second fin area;
• forming an isolation layer on a side surface of a lower portion of the active fin;
• forming a sacrificial gate on the first fin area of the active fin and the isolation layer;
• forming a recessed second fin area by etching the second fin area, after forming the sacrificial gate;
• forming a diamond-shaped source/drain on the recessed second fin area;
• forming an interlayer insulating layer on the diamond-shaped source/drain and the isolation layer;
• forming a gate trench by removing the sacrificial gate, after forming the interlayer insulating layer;
• and
• forming a gate structure in the gate trench,
• wherein the diamond-shaped source/drain comprises a first crystal growth portion and a second crystal growth portion, and
• wherein the second crystal growth portion comprises a lower surface that is at a lower level than a lower surface of the first crystal growth portion.