Semiconductor device structure with salicide layer and method for forming the same

A method for forming a semiconductor device structure, comprising:

• forming a first fin structure and a second fin structure over a substrate;
• forming an isolation feature to surround a lower portion of the first fin structure and a lower portion of the second fin structure;
• after forming the isolation feature, forming a gate structure across the first fin structure and the second fin structure;
• after forming the gate structure, forming a first fin spacer, a second fin spacer, a third spacer and a fourth spacer over the isolation feature, wherein an upper portion of the first fin structure is sandwiched between the first fin spacer and the second fin spacer, and an upper portion of the second fin structure is sandwiched between the third fin spacer and the fourth fin spacer;
• after forming the gate structure, forming gate spacers over sidewalls of the gate structure;
• removing the upper portion of the first fin structure to form a first recess extending between the first fin spacer and the second fin spacer and removing the upper portion of the second fin structure to form a second recess extending between the third fin spacer and the fourth fin spacer;
• forming a source/drain structure over the first fin structure and the second fin structure and adjacent to the gate structure, wherein the source/drain structure includes a first bottom portion in the first recess, a second bottom portion in the second recess, and an upper portion protruding from the first recess and the second recess and wider than the first bottom portion and the second bottom portion;
• forming a sacrificial liner over the source/drain structure;
• forming a dummy material layer to cover the sacrificial liner, wherein the sacrificial liner is made of a different material than the dummy material layer;
• replacing the gate structure by a metal gate structure after the dummy material layer is formed;
• forming a mask structure over a top surface of the metal gate structure;
• removing the dummy material layer to expose the source/drain structure;
• forming a metal layer over the gate spacers and the source/drain structure, wherein the metal layer contacts a sidewall of the mask structure;
• forming a salicide layer covering the source/drain structure, wherein the salicide layer extends continuously from the first fin spacer to the fourth fin spacer, and a bottom portion of the salicide layer extends below the upper portion of the source/drain structure;
• forming a capping layer over the salicide layer, wherein a portion of the capping layer directly below the bottom portion of the salicide layer is in contact with a sidewall of the first fin spacer;
• forming a dielectric layer to cover the capping layer, wherein the dielectric layer is made of a different material than the capping layer;
• etching the dielectric layer to form a trench exposing the salicide layer;
• and
• forming a contact in the trench.

A method for forming a semiconductor device structure, comprising:

• forming a fin structure and an isolation feature over a substrate, wherein a lower portion of the fin structure is embedded in the isolation feature;
• forming a first gate structure over the fin structure;
• after forming the first gate structure, forming fin spacers on the isolation feature and surrounding an upper portion of the fin structure;
• removing a portion of the fin structure to form a recess extending between the fin spacers;
• forming a source/drain structure from the recess, wherein the source/drain structure includes a bottom portion in the recess and an upper portion protruding from the recess and wider than the bottom portion;
• forming a sacrificial material layer to cover the source/drain structure;
• replacing the first gate structure with a second gate structure;
• removing the sacrificial material layer to expose the source/drain structure;
• forming a salicide layer along the source/drain structure, wherein a bottom portion of the salicide layer extends below the upper portion of the source/drain structure;
• forming a capping layer over the salicide layer, wherein a portion of the capping layer directly below the bottom portion of the salicide layer is in contact with a sidewall of one of the fin spacers;
• forming a dielectric layer to cover the capping layer, wherein the dielectric layer is made of a different material than the capping layer;
• and
• forming a contact through the dielectric layer to land on the salicide layer.