Semiconductor device including source/drain pattern with main layer and buffer layer having germanium and method of fabricating the same
A semiconductor device includes a substrate including a p-type metal-oxide-semiconductor (MOS) field-effect transistor (FET) (PMOSFET) region and an n-type MOSFET (NMOSFET) region, a first active pattern on the PMOSFET region, a second active pattern on the NMOSFET region, a first channel pattern and a first source/drain pattern on the first active pattern, the first channel pattern connected to the first source/drain pattern, a second channel pattern and a second source/drain pattern provided on the second active pattern, the second channel pattern connected to the second source/drain pattern, and a gate electrode on the first channel pattern and the second channel pattern.
1 . A semiconductor device, comprising:
a substrate comprising a p-type metal-oxide-semiconductor (MOS) field-effect transistor (FET) (PMOSFET) region and an n-type MOSFET (NMOSFET) region;
a first active pattern on the PMOSFET region;
a second active pattern on the NMOSFET region;
a first channel pattern and a first source/drain pattern on the first active pattern, the first channel pattern connected to the first source/drain pattern;
a second channel pattern and a second source/drain pattern provided on the second active pattern, the second channel pattern connected to the second source/drain pattern; and
a gate electrode on the first channel pattern and the second channel pattern,
wherein the first source/drain pattern comprises a first buffer layer and a first main layer on the first buffer layer,
wherein the second source/drain pattern comprises a second buffer layer and a second main layer on the second buffer layer,
wherein each of the first buffer layer and the second buffer layer comprises silicon-germanium (SiGe),
wherein a germanium concentration in each of the first buffer layer and the second buffer layer is in a range from 2 at % to 30 at %,
wherein a germanium concentration of the first source/drain pattern increases in a first direction that is away from the substrate, and
wherein a germanium concentration in the second source/drain pattern decreases in the first direction.
2 . The semiconductor device of claim 1 , wherein the first main layer comprises silicon-germanium (SiGe), and
wherein a germanium concentration in the first main layer is higher than the germanium concentration in the first buffer layer.
3 . The semiconductor device of claim 1 , wherein the second main layer comprises silicon, and
wherein the germanium concentration in the second buffer layer is higher than a germanium concentration in the second main layer.
4 . The semiconductor device of claim 1 , wherein the first buffer layer comprises a first impurity comprising at least one of boron, gallium, and indium, and
wherein the second buffer layer comprises a second impurity comprising at least one of phosphorus, arsenic, and antimony.
5 . The semiconductor device of claim 1 , further comprising:
a gate insulating layer between the gate electrode and each of the first and second channel patterns; and
a gate spacer on a side surface of the gate electrode,
wherein the gate insulating layer is between the gate electrode and the gate spacer, and
wherein a first horizontal distance between the gate insulating layer and a first upper side surface of the first buffer layer is equal to a second horizontal distance between the gate insulating layer and a second upper side surface of the second buffer layer.
6 . The semiconductor device of claim 1 , wherein the second main layer comprises an upper portion comprising at least one facet surface, and
wherein the at least one facet surface is a { 111 } plane.
7 . The semiconductor device of claim 1 , wherein the second channel pattern comprises a first semiconductor pattern, a second semiconductor pattern, and a third semiconductor pattern spaced apart from each other,
wherein the second buffer layer comprises a first thickness between the third semiconductor pattern and the second main layer,
wherein the second buffer layer comprises a second thickness between the second semiconductor pattern and the second main layer,
wherein the second buffer layer comprises a third thickness between the first semiconductor pattern and the second main layer, and
wherein each of the first thickness, the second thickness and the third thickness are different from each other.
8 . The semiconductor device of claim 7 , wherein the third thickness is larger than the second thickness, and
wherein the first thickness is larger than the third thickness.
9 . The semiconductor device of claim 1 , further comprising a gate spacer on a side surface of the gate electrode,
wherein a side portion of the first buffer layer contacts the gate spacer, and
wherein a ratio of a thickness of the side portion of the first buffer layer to a thickness of a center portion of the first buffer layer is in a range from 0.7 to 1.
10 . A semiconductor device, comprising:
a substrate comprising an n-type metal-oxide-semiconductor (MOS) field-effect transistor (FET) (NMOSFET) region;
an active pattern on the NMOSFET region;
a channel pattern on the active pattern, the channel pattern comprising a plurality of semiconductor patterns spaced apart from each other;
a source/drain pattern on the active pattern;
a gate electrode on the channel pattern, the gate electrode comprising:
an inner electrode between adjacent semiconductor patterns of the plurality of semiconductor patterns; and
an outer electrode on a uppermost semiconductor pattern of the plurality of semiconductor patterns;
a gate insulating layer between the gate electrode and each of the plurality of semiconductor patterns;
a gate spacer on a side surface of the outer electrode;
a gate capping pattern on a top surface of the outer electrode;
an interlayer insulating layer on the gate capping pattern and the source/drain pattern;
a gate contact penetrating the interlayer insulating layer and the gate capping pattern, the gate contact connected to the gate electrode;
an active contact penetrating the interlayer insulating layer and connected to the source/drain pattern;
a first metal layer on the interlayer insulating layer, the first metal layer comprising a plurality of first interconnection lines respectively connected to the gate contact and the active contact; and
a second metal layer on the first metal layer,
wherein the second metal layer comprises a plurality of second interconnection lines connected to the first metal layer,
wherein the source/drain pattern comprises a buffer layer and a main layer on the buffer layer,
wherein the main layer comprises an upper portion comprising at least one facet surface,
wherein the at least one facet surface is a { 111 } plane, and
wherein the buffer layer at least partially covers the at least one facet surface.
11 . The semiconductor device of claim 10 , wherein the buffer layer comprises silicon-germanium (SiGe), and
wherein a germanium concentration in the buffer layer is in a range from 2 at % to 30 at %.
12 . The semiconductor device of claim 10 , wherein the main layer comprises silicon, and
wherein a silicon concentration in the main layer is in a range from 90 at % to 100 at %.
13 . The semiconductor device of claim 10 , wherein the plurality of semiconductor patterns comprise a first semiconductor pattern, a second semiconductor pattern, and a third semiconductor pattern, which are sequentially stacked,
wherein the buffer layer comprises a first thickness between the third semiconductor pattern and the main layer,
wherein the buffer layer comprises a second thickness between the second semiconductor pattern and the main layer,
wherein the buffer layer comprises a third thickness between the first semiconductor pattern and the main layer, and
wherein the first thickness, the second thickness and the third thickness are different from each other.
14 . The semiconductor device of claim 13 , wherein the third thickness is larger than the second thickness, and
wherein the first thickness is larger than the third thickness.