Semiconductor device and manufacturing method thereof

A semiconductor device comprising:

• a gate structure located on a substrate, and an interface between the gate structure and the substrate;
• a raised source/drain region adjacent to the gate structure, wherein the raised source/drain region comprises an epitaxially grown material selected to exhibit a tensile or compressive stress provided to a channel region under the gate structure, the epitaxially grown material includes:
• a first epitaxial-grown doped layer;
• a second epitaxial-grown doped layer over the first epitaxial-grown doped layer, the second epitaxial-grown doped layer including a dopant concentration higher than that of the first epitaxial-grown doped layer;
• and
• a silicide plug, wherein the silicide plug penetrates a top surface of the raised source/drain region and extends into the second epitaxial-grown doped layer, and a bottommost portion of the silicide layer ends below the interface by a predetermined depth so as to enlarge a contact area coupling with the raised source/drain region, and the predetermined depth is allowed to reduce contact resistance and maintain the tensile or compressive stress of the channel region.

A semiconductor device comprising:

• a gate structure located on a substrate, and an interface between the gate structure and the substrate;
• a raised source/drain region adjacent to the gate structure, wherein the raised source/drain region comprises:
• an epitaxial-grown doped layer providing a tensile or compressive stress to a channel region under the gate structure, wherein from bottom to top, the epitaxial-grown doped layer includes a first epitaxial-grown doped layer and a second epitaxial-grown doped layer;
• a silicon cap layer capping the epitaxial-grown doped layer;
• and
• a silicide layer, penetrating a top surface of the raised source/drain region and extending into at least the second epitaxial-grown doped layer, and the silicide layer being partially below the interface by a predetermined depth, wherein the predetermined depth allows the epitaxial-grown doped layer to maintain the strain of the channel region.