Semiconductor structure with blocking layer and method for forming the same

A method for forming a semiconductor structure, comprising:

• forming a gate structure over a first fin structure;
• forming a source/drain structure in the first fin structure and adjacent to the gate structure, wherein forming the source/drain structure comprises:
• growing a first epitaxial layer over the first fin structure;
• and
• growing a second epitaxial layer over the first epitaxial layer;
• forming a dielectric layer over the gate structure and the source/drain structure;
• removing a portion of the dielectric layer and a portion of the source/drain structure to form an opening;
• forming a silicide layer in the opening, wherein a bottom surface of the silicide layer is between a top surface of the second epitaxial layer and a top surface of the first fin structure;
• forming a blocking layer over the second epitaxial layer and the silicide layer;
• and
• forming a contact structure filing the opening, wherein a sidewall surface of the contact structure is surrounded by the blocking layer.

A method for forming a semiconductor structure, comprising:

• forming a gate structure over a fin structure;
• forming a source/drain structure in the fin structure and adjacent to the gate structure, wherein the source/drain structure has a width along a (110) plane;
• selectively etching the source/drain structure to reduce the width of the source/drain structure;
• forming a dielectric layer over the gate structure and the source/drain structure;
• removing a portion of the dielectric layer and a portion of the source/drain structure to form an opening, wherein a first surface of the source/drain structure in the opening is above a top surface of the fin structure;
• depositing a blocking layer lining a sidewall surface of the opening and on the first surface of the source/drain structure;
• removing a portion of the blocking layer in the opening;
• and
• forming a contact structure filling the opening in the dielectric layer, wherein a sidewall surface of the contact structure is surrounded by the blocking layer.