Semiconductor structure with barrier layer 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;
• a contact structure passing through the dielectric layer;
• a glue layer covering a bottom surface and a sidewall surface of the contact structure;
• and
• a barrier layer between the dielectric layer and the glue layer, wherein a portion of the barrier layer and a portion of the contact structure are embedded in the source/drain structure.

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 dielectric layer over the gate structure and the source/drain structure;
• forming an opening in the dielectric layer to expose the source/drain structure;
• depositing a barrier layer lining a sidewall surface of the opening and a top surface of the source/drain structure;
• etching a portion of the barrier layer to expose the source/drain structure;
• depositing a glue layer covering the sidewall surface of the opening and the source/drain structure in the opening;
• and
• forming a contact structure filling the opening in the dielectric layer, wherein the contact structure is surrounded by the glue layer.