Semiconductor device having contact plug and method of forming the same
A semiconductor device includes an N-type fin and a P-type fin on a substrate, a first gate electrode configured to cross the N-type fin and cover a side surface of the N-type fin, a second gate electrode configured to cross the P-type fin and cover a side surface of the P-type fin, a first source/drain on the N-type fin adjacent to the first gate electrode, a second source/drain on the P-type fin adjacent to the second gate electrode, a buffer layer on a surface of the second source/drain and including a material different from the second source/drain, an interlayer insulating layer on the buffer layer and the first source/drain, a first plug connected to the first source/drain and passing through the interlayer insulating layer, and a second plug connected to the second source/drain and passing through the interlayer insulating layer and the buffer layer.
1. A semiconductor device, comprising:
an N-type fin and a P-type fin on a substrate;
a first gate electrode configured to cross the N-type fin and cover a side surface of the N-type fin;
a second gate electrode configured to cross the P-type fin and cover a side surface of the P-type fin;
a first source/drain on the N-type fin adjacent to the first gate electrode;
a second source/drain on the P-type fin adjacent to the second gate electrode;
a buffer layer on a surface of the second source/drain, the buffer layer including a material different from the second source/drain;
an interlayer insulating layer on the buffer layer and the first source/drain;
a first plug connected to the first source/drain, the first plug passing through the interlayer insulating layer; and
a second plug connected to the second source/drain, the second plug passing through the interlayer insulating layer and the buffer layer.
2. The semiconductor device of claim 1 , wherein
a center portion of the second source/drain has a horizontal width greater than a horizontal width of a lower portion, and
the buffer layer directly contacts the lower portion of the second source/drain.
3. The semiconductor device of claim 1 , wherein the buffer layer includes a crystal growth material.
4. The semiconductor device of claim 1 , wherein the buffer layer includes germanium (Ge).
5. The semiconductor device of claim 1 , further comprising:
a plug ion implantation region between the first source/drain and the first plug,
wherein a P-type impurity concentration in the plug ion implantation region is greater than a P-type impurity concentration in the first source/drain.
6. The semiconductor device of claim 5 , wherein the buffer layer has a thickness greater than the plug ion implantation region.
7. The semiconductor device of claim 1 , wherein
a thickness of the buffer layer is 3 nm or more, and
the thickness of the buffer layer is smaller than a thickness of the interlayer insulating layer.
8. The semiconductor device of claim 1 , wherein
the first source/drain includes at least one of silicon germanium (SiGe), silicon (Si), boron (B) and boron monofluoride (BF), and
the second source/drain includes at least one of silicon carbide (SiC), silicon (Si), phosphorus (P) and arsenic (As).
9. The semiconductor device of claim 1 , wherein a lower portion of the second plug has a horizontal width greater than a horizontal width of a center portion.
10. The semiconductor device of claim 1 , further comprising:
an under-cut region under the interlayer insulating layer,
wherein the second plug extends into the under-cut region and contacts the buffer layer.
11. The semiconductor device of claim 1 , further comprising:
a first metal silicide layer between the first plug and the first source/drain; and
a second metal silicide layer between the second plug and the second source/drain.
12. A semiconductor device, comprising:
a first fin on a substrate, the first fin having a first conductivity type;
a first gate electrode configured to cross the first fin and cover a side surface of the first fin;
a first source/drain on the first fin and adjacent to the first gate electrode, the first source/drain having a second conductivity type different from the first conductivity type;
a buffer layer on a surface of the first source/drain, the buffer layer including a material different from the first source/drain;
an interlayer insulating layer on the buffer layer; and
a first plug connected to the first source/drain, the first plug passing through the interlayer insulating layer and the buffer layer.
13. The semiconductor device of claim 12 , further comprising:
a second fin spaced apart from the first fin on the substrate, the second fin having the second conductivity type;
a second gate electrode configured to cross the second fin and cover a side surface of the second fin;
a second source/drain on the second fin and adjacent to the second gate electrode, the second source/drain having the first conductivity type; and
a second plug connected to the second source/drain, the second plug passing through the interlayer insulating layer,
wherein the interlayer insulating layer is on the second source/drain.
14. The semiconductor device of claim 13 , further comprising:
a plug ion implantation region between the second source/drain and the second plug.
15. The semiconductor device of claim 14 , wherein the buffer layer has a thickness greater than the plug ion implantation region.
16. A semiconductor device, comprising:
a plurality of first fins on a substrate and in parallel, the plurality of first fins having a first conductivity type;
a first gate electrode configured to cross the first fins and cover side surfaces of the first fins;
first source/drains on the first fins and adjacent to the first gate electrode, the first source/drains having a second conductivity type different from the first conductivity type;
a buffer layer on a surface of the first source/drains, the buffer layer including a material different from the first source/drains;
an interlayer insulating layer on the buffer layer; and
a first plug connected to the first source/drains, the first plug passing through the interlayer insulating layer and the buffer layer.
17. The semiconductor device of claim 16 , further comprising:
a plurality of second fins spaced apart from the first fins on the substrate and in parallel, the second fins having the second conductivity type;
a second gate electrode configured to cross the second fins and cover side surfaces of the second fins;
second source/drains on the second fins and adjacent to the second gate electrode, the second source/drains having the first conductivity type; and
a second plug connected to the second source/drains, the second plug passing through the interlayer insulating layer,
wherein the interlayer insulating layer is on the second source/drains.
18. The semiconductor device of claim 17 , further comprising:
a plug ion implantation region between the second source/drains and the second plug.
19. The semiconductor device of claim 18 , wherein the buffer layer has a thickness greater than the plug ion implantation region.
20. The semiconductor device of claim 12 , wherein the buffer layer includes germanium (Ge).