Semiconductor device including epitaxial region having an extended portion

A semiconductor device, comprising:

• an active region on a semiconductor substrate;
• a channel region on the active region;
• a source/drain region adjacent to the channel region on the active region;
• a gate structure overlapping the channel region, on the channel region;
• a contact structure on the source/drain region;
• a gate spacer between the contact structure and the gate structure;
• and
• a contact spacer surrounding a side surface of the contact structure,
• wherein the source/drain region includes a base epitaxial region, a first epitaxial region on the base epitaxial region, and a second epitaxial region on the first epitaxial region,
• wherein the source/drain region includes a Si element and a Ge element,
• wherein a Ge element concentration in the base epitaxial region, a Ge element concentration in the first epitaxial region, and a Ge element concentration in the second epitaxial region are different from each other,
• wherein the second epitaxial region includes an extended portion, extending in a horizontal direction from a portion overlapping the contact structure in a vertical direction to a portion overlapping the contact spacer in the vertical direction,
• wherein the second epitaxial region is spaced apart from the channel region, and
• wherein a portion of the base epitaxial region is between the second epitaxial region and the channel region.

A semiconductor device, comprising:

• an active region on a semiconductor substrate;
• a channel region on the active region;
• a source/drain region adjacent to the channel region on the active region;
• a gate structure overlapping the channel region, on the channel region;
• a contact structure on the source/drain region;
• a gate spacer between the contact structure and the gate structure;
• and
• a contact spacer surrounding a side surface of the contact structure,
• wherein the source/drain region includes a first epitaxial region having a recessed surface and a second epitaxial region on the recessed surface of the first epitaxial region,
• wherein the second epitaxial region includes an extended portion, extending in a horizontal direction from a portion overlapping the contact structure in a vertical direction to a portion overlapping the contact spacer in the vertical direction, and
• wherein the extended portion of the second epitaxial region overlaps the gate spacer in the vertical direction.