Semiconductor structure with blocking layer
A semiconductor structure is provided. The semiconductor structure includes a gate structure over a fin structure, and a source/drain structure in the fin structure and adjacent to the gate structure. The source/drain structure includes: a first epitaxial layer over the fin structure, a second epitaxial layer over the first epitaxial layer, and an epitaxial capping layer over the second epitaxial layer. The semiconductor structure also includes a silicide layer formed in contact with the source/drain structure. The silicide layer has a curved bottom surface, and the curved bottom surface of the silicide layer intersects with the second epitaxial layer and the epitaxial capping layer.
1 . A semiconductor structure, comprising:
a gate structure having a gate dielectric layer over a fin structure;
gate spacers formed on opposite sidewalls of the gate structure and over the fin structure;
a source/drain structure in the fin structure and adjacent to the gate structure, wherein the source/drain structure comprises:
a first epitaxial layer in contact with a top surface of the fin structure;
a second epitaxial layer over the first epitaxial layer; and
a capping epitaxial layer over the second epitaxial layer;
a contact structure extending over the source/drain structure;
a blocking layer formed around the contact structure;
a glue layer covering a bottom surface and a sidewall surface of the contact structure; and
a silicide layer formed between the source/drain structure and the contact structure, wherein a top surface and a bottom surface of the silicide layer extend from and end at an interface between the glue layer and the blocking layer, the bottom surface of the silicide layer is lower than a bottom end of the blocking layer, and a horizontal plane passes through the bottom surface of the silicide layer and the second epitaxial layer,
wherein the top surface of the silicide layer is a curved interface between the glue layer and the silicide layer, and the bottom surface of the silicide layer is a curved surface in contact with the second epitaxial layer and the capping epitaxial layer.
2 . The semiconductor structure as claimed in claim 1 , wherein the glue layer separates the contact structure from the silicide layer.
3 . The semiconductor structure as claimed in claim 2 , wherein the glue layer is conformally formed along the sidewall surface of the contact structure and the top surface of the silicide layer.
4 . The semiconductor structure as claimed in claim 1 , wherein the blocking layer and the gate spacers are formed of the same material.
5 . The semiconductor structure as claimed in claim 1 , wherein an interface between the first epitaxial layer and the second epitaxial layer is curved.
6 . The semiconductor structure as claimed in claim 1 , wherein an interface between the second epitaxial layer and the capping epitaxial layer is curved.
7 . The semiconductor structure as claimed in claim 1 , wherein the silicide layer comprises cobalt, titanium, nickel, copper, tungsten, and molybdenum.
8 . The semiconductor structure as claimed in claim 1 , wherein the blocking layer extends into the source/drain structure.
9 . The semiconductor structure as claimed in claim 1 , wherein the first epitaxial layer intersects with the gate spacers.
10 . The semiconductor structure as claimed in claim 1 , wherein the bottom end of the blocking layer and a bottom end of the gate spacers are located at different heights.
11 . 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, wherein the source/drain structure comprises:
a first epitaxial layer in contact with a top surface of the fin structure;
a second epitaxial layer over the first epitaxial layer; and
a capping epitaxial layer over the second epitaxial layer;
a dielectric layer over the source/drain structure and the gate structure;
a blocking layer penetrating the dielectric layer and connected to the source/drain structure;
a glue layer covering a bottom surface and a sidewall surface of the contact structure; and
a silicide layer surrounded by the blocking layer, wherein a top surface and a bottom surface of the silicide layer extend from and end at an interface between the glue layer and the blocking layer, the bottom surface of the silicide layer is lower than a bottom end of the blocking layer, and a horizontal plane passes through the bottom surface of the silicide layer and the second epitaxial layer,
wherein the top surface of the silicide layer is a curved interface between the glue layer and the silicide layer, and the bottom surface of the silicide layer is a curved surface in contact with the second epitaxial layer and the capping epitaxial layer.
12 . The semiconductor structure as claimed in claim 11 , wherein a curvature of the top surface of the silicide layer is different from a curvature of the bottom surface of the silicide layer.
13 . The semiconductor structure as claimed in claim 11 , wherein the top surface of the silicide layer is lower than the bottom end of the blocking layer, and a horizontal plane passes through the top surface of the silicide layer and the capping epitaxial layer.
14 . The semiconductor structure as claimed in claim 11 , wherein a thickness of the silicide layer gradually increases from an edge of the silicide layer to a center of the silicide layer.
15 . The semiconductor structure as claimed in claim 11 , wherein the silicide layer is adjacent to the blocking layer when viewed in a direction perpendicular to the horizontal plane.
16 . A semiconductor structure, comprising:
a gate structure having a gate dielectric layer and a gate electrode layer over a fin structure;
a source/drain structure in the fin structure and adjacent to the gate structure, wherein the source/drain structure comprises:
a first epitaxial layer in contact with a top surface of the fin structure;
a second epitaxial layer over the first epitaxial layer; and
a capping epitaxial layer over the second epitaxial layer;
a contact structure extending over the source/drain structure;
a blocking layer formed around the contact structure;
a glue layer covering a bottom surface and a sidewall surface of the contact structure; and
a silicide layer, wherein a top surface and a bottom surface of the silicide layer extend from and end at an interface between the glue layer and the blocking layer, the bottom surface of the silicide layer is lower than a bottom end of the blocking layer, a horizontal plane passes through the bottom surface of the silicide layer and the second epitaxial layer, and the silicide layer overlaps with the contact structure in a direction perpendicular to the horizontal plane,
wherein the top surface of the silicide layer is a curved interface between the glue layer and the silicide layer, and the bottom surface of the silicide layer is a curved surface in contact with the second epitaxial layer and the capping epitaxial layer.
17 . The semiconductor structure as claimed in claim 16 , wherein the silicide layer is located between a top surface and a bottom surface of the gate structure in the direction perpendicular to the horizontal plane.
18 . The semiconductor structure as claimed in claim 16 , wherein a bottom surface of the glue layer is lower than the bottom end of the blocking layer.
19 . The semiconductor structure as claimed in claim 18 , wherein the glue layer separates the contact structure from the blocking layer.
20 . The semiconductor structure as claimed in claim 18 , wherein the glue layer contacts the top surface of the silicide layer and the bottom end of the blocking layer.