Methods of forming epitaxial source/drain features in semiconductor devices

A semiconductor structure, comprising:

• semiconductor fins disposed over a substrate;
• an epitaxial source/drain (S/D) feature over the semiconductor fins, wherein the epitaxial S/D feature includes a first Ge-containing layer embedded in a second Ge-containing layer, wherein the first Ge-containing layer merges together the semiconductor fins, and wherein a top surface of the second Ge-containing layer defines a top surface of the epitaxial S/D feature;
• an etch stop layer over the substrate and extends along sidewall surfaces of the second Ge-containing layer;
• an interlayer dielectric (ILD) layer disposed on the etch stop layer;
• a silicide layer contacting the top surface of the epitaxial S/D feature, wherein the silicide layer includes slanted portions that form a downward angle over the top surface of the epitaxial S/D feature;
• and
• a S/D contact disposed in the etch stop layer and the ILD layer to contact the silicide layer.

A semiconductor structure, comprising:

• semiconductor fins disposed over a substrate;
• a p-type source/drain (S/D) feature disposed over the semiconductor fins, wherein the p-type S/D feature includes a first Ge-containing layer in direct contact with the semiconductor fins and a second Ge-containing layer in direct contact with and surrounding the first Ge-containing layer, and a concentration of germanium in the second Ge-containing layer is no less than twice of a concentration of germanium in the first Ge-containing layer;
• an etch-stop layer (ESL) in direct contact with sidewall surfaces of the second Ge-containing layer;
• an interlayer dielectric (ILD) layer disposed over the ESL;
• a silicide layer contacting a top surface of the p-type S/D feature, wherein the silicide layer includes a first slanted surface and a second slanted surface meeting at an angle;
• and
• a S/D contact disposed in the ILD layer, wherein a bottom portion of the S/D contact is defined by the first and the second slanted surfaces, such that a lowest point of the S/D contact extends downward and away from a sidewall of the S/D contact.