Semiconductor structure with doped via plug and method for forming the same

A semiconductor structure, comprising:

• a gate structure over a fin structure;
• a source/drain structure in the fin structure and adjacent to the gate structure;
• a dielectric layer over the gate structure and the source/drain structure;
• and
• a via plug passing through the dielectric layer, wherein the via plug comprises a first group IV element, and the dielectric layer comprises a second group IV element.

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;
• forming a contact plug over the source/drain structure;
• forming a dielectric layer over the contact plug;
• forming an opening in the dielectric layer to expose the contact plug;
• depositing a metal material to fill the opening;
• implanting a first group IV element into the metal material;
• and
• removing a portion of the metal material above a top surface of the dielectric layer to form a via plug over the contact plug.