Wraparound contact with reduced distance to channel
A nanosheet semiconductor device includes channel nanosheets each connected to a source/drain region that has a front surface, a rear surface, and an internal recess between the front surface and the rear surface. The device further includes a source/drain region contact in physical contact with the V shaped internal recess, with the front surface, and with the rear surface. The device may be fabricated by forming the source/drain region, recessing the source/drain region, and by forming a sacrificial source/drain region upon and around the recessed source/drain region. The sacrificial source/drain region may be removed and the source/drain region contact may be formed in place thereof.
1. A nanosheet semiconductor device comprising:
a plurality of channel nanosheets each connected to a source/drain region;
a gate surrounding the plurality of channel nanosheets;
the source/drain region comprising a front surface, a rear surface, a top surface, and an internal recess comprising two or more sloped internal surfaces extending downward from the top surface; and
a source/drain region contact in physical contact with the internal recess, in physical contact with the front surface, and in physical contact with the rear surface of the source/drain region.
2. The nanosheet semiconductor device of claim 1 , wherein the two or more sloped internal surfaces intersect at a bottom vertex of the internal recess.
3. The nanosheet semiconductor device of claim 2 , wherein the bottom vertex is concave.
4. The nanosheet semiconductor device of claim 3 , wherein the source/drain region contact is further in physical contact with the top surface of the source/drain region.
5. The nanosheet semiconductor device of claim 1 , wherein the source/drain region contact comprises a conical upper portion and a lower portion, wherein the lower portion comprises a rectangular cuboid portion above a triangular prism portion, wherein the rectangular cuboid portion is in physical contact with the top surface of the source/drain region, and wherein the triangular prism portion is in physical contact with the internal recess of the source/drain region.
6. The nanosheet semiconductor device of claim 5 , wherein the source/drain region contact further comprises a front portion that extends downward from the rectangular cuboid portion and a rear portion that extends downward from the rectangular cuboid portion.
7. The nanosheet semiconductor device of claim 6 , wherein the front portion of the source/drain region contact is in physical contact with the front surface of the source/drain region and wherein the rear portion of the source/drain region contact is in physical contact with the rear surface of the source/drain region.
8. The nanosheet semiconductor device of claim 1 , wherein the source/drain region contact extends below one or more of the plurality of channel nanosheets.
9. The nanosheet semiconductor device of claim 1 , wherein the source/drain region contact extends below two or more of the plurality of channel nanosheets.
10. A nanosheet semiconductor device comprising:
a plurality of channel nanosheets each connected to a source/drain region, the source/drain region comprising a front surface, a rear surface, and a V shaped internal recess between the front surface and the rear surface; and
a source/drain region contact comprising an inner portion in physical contact with the V shaped internal recess, a front portion in physical contact with the front surface, and a rear portion in physical contact with the rear surface.
11. The nanosheet semiconductor device of claim 10 , wherein the inner portion of the source/drain region contact comprises a bottom vertex at a bottom of the V shaped internal recess.
12. The nanosheet semiconductor device of claim 11 , wherein the bottom vertex is concave between the front portion and the rear portion.
13. The nanosheet semiconductor device of claim 12 , wherein the source/drain region further comprises a top surface.
14. The nanosheet semiconductor device of claim 10 , wherein the source/drain region contact further comprises a rectangular cuboid portion in physical contact with an upper surface of the source/drain region.
15. The nanosheet semiconductor device of claim 13 , wherein a distance between a bottom most channel nanosheet and the bottom vertex is less than a distance between the bottom most channel nanosheet and the top surface of the source/drain region.
16. The nanosheet semiconductor device of claim 11 , wherein the bottom vertex is below a top surface of a top channel nanosheet.
17. The nanosheet semiconductor device of claim 11 , wherein the bottom vertex is below one or more of the plurality of channel nanosheets.
18. The nanosheet semiconductor device of claim 11 , wherein the bottom vertex is below two or more of the plurality of channel nanosheets.
19. A semiconductor device comprising:
a source/drain region comprising a side surface in physical contact with a plurality of nanosheets, a front surface, a rear surface, a top surface, and an internal recess that extends from the front surface to the rear surface and comprises two or more sloped internal surfaces extending downward from the top surface; and
a source/drain region contact in physical contact with the internal recess.
20. The semiconductor device of claim 19 , wherein the source/drain region contact is also in physical contact with the front surface of the source/drain region and the rear surface of the source/drain region.