FinFET device and methods of forming
A finFET device and methods of forming a finFET device are provided. The method includes depositing a dummy gate over and along sidewalls of a fin extending upwards from a semiconductor substrate, forming a first gate spacer along a sidewall of the dummy gate, and plasma-doping the first gate spacer with carbon to form a carbon-doped gate spacer. The method further includes forming a source/drain region adjacent a channel region of the fin and diffusing carbon from the carbon-doped gate spacer into a first region of the fin to provide a first carbon-doped region. The first carbon-doped region is disposed between at least a portion of the source/drain region and the channel region of the fin.
1. A fin field effect transistor (finFET) device comprising:
a fin extending upwards from a semiconductor substrate;
a gate stack over and along sidewalls of a channel region of the fin;
a source/drain region adjacent the fin;
a gate spacer disposed along a sidewall of the gate stack;
a first carbon-doped region disposed along a bottom surface and a sidewall of the source/drain region, wherein the first carbon-doped region is between the sidewall of the source/drain region and the channel region along a line parallel to a major surface of the semiconductor substrate; and
a second carbon-doped region under the gate spacer and between the first carbon-doped region and the channel region, wherein the first carbon-doped region and the second carbon-doped region have different concentrations of carbon.
2. The finFET device of claim 1 , wherein the second carbon-doped region is disposed in a lightly-doped drain (LDD) region of the finFET device.
3. The finFET device of claim 1 , wherein the gate spacer comprises carbon dopants.
4. The finFET device of claim 1 , wherein the second carbon-doped region has a lower concentration of carbon than the first carbon-doped region.
5. The finFET device of claim 4 , wherein a carbon concentration of the first carbon-doped region is 3×10 20 cm −3 or greater, and wherein a carbon concentration of the second carbon-doped region is in the range of 1×10 19 cm −3 to 5×10 1 cm −3 .
6. The finFET device of claim 1 , wherein a ratio of a carbon concentration of the first carbon-doped region at a top of the fin to carbon concentrations of the first carbon-doped region at a sidewall of the fin to a carbon concentration of the first carbon-doped region at a bottom of the fin is in the range of 1:0.65:0.65 to 1:0.9:0.9.
7. The finFET device of claim 1 , wherein the first carbon-doped region extends lower than the second carbon-doped region.
8. The finFET device of claim 1 , wherein a carbon concentration of the first carbon-doped region increases in a direction towards the source/drain region.
9. A fin field effect transistor (finFET) device comprising:
a semiconductor fin disposed between isolation regions;
a gate stack over and along sidewalls of a channel region of the semiconductor fin, wherein the channel region is doped with carbon;
a source/drain region adjacent the semiconductor fin;
a carbon-doped gate spacer disposed along a sidewall of the gate stack;
a carbon film over the carbon-doped gate spacer, wherein the carbon film extends along the sidewall of the gate stack; and
a first carbon-doped region under the carbon-doped gate spacer.
10. The finFET device of claim 9 further comprising a second carbon-doped region disposed along sidewalls and a bottom surface of the source/drain region.
11. The finFET device of claim 10 , wherein the second carbon-doped region is disposed between at least a portion of the source/drain region and the first carbon-doped region.
12. The finFET device of claim 10 , wherein the first carbon-doped region has a lower concentration of carbon than the second carbon-doped region.
13. The finFET device of claim 10 , wherein the second carbon-doped region extends under the carbon-doped gate spacer.
14. The finFET device of claim 9 further comprising one or more additional gate spacers over the carbon film, wherein the one or more additional gate spacers extend along the sidewall of the gate stack.
15. A fin field effect transistor (finFET) device comprising:
a semiconductor fin extending from a semiconductor substrate;
a gate stack over and along sidewalls of the semiconductor fin;
a carbon-comprising gate spacer disposed along a sidewall of the gate stack;
a lightly doped drain (LDD) region under the carbon-comprising gate spacer, wherein the LDD region comprises carbon;
an epitaxial source/drain region adjacent the LDD region; and
carbon-doped semiconductor liner disposed along sidewalls and a bottom surface of the epitaxial source/drain region, wherein the carbon-doped semiconductor liner is disposed between the LDD region and a sidewall of the epitaxial source/drain region along a line parallel to a major surface of the semiconductor substrate, the carbon-doped semiconductor liner having a different concentration of carbon than the LDD region.
16. The finFET device of claim 15 , wherein the epitaxial source/drain region and the carbon-doped semiconductor liner extends under the carbon-comprising gate spacer.
17. The finFET device of claim 15 , wherein the carbon-doped semiconductor liner has a carbon concentration of 3×10 20 cm −3 or greater.
18. The finFET device of claim 15 , wherein the LDD region has a carbon concentration in the range of 1×10 19 cm −3 to 5×10 1 cm −3 .
19. The finFET device of claim 15 , wherein a channel region of the semiconductor fin comprises carbon.
20. The finFET device of claim 15 , wherein an interface between the carbon-doped semiconductor liner and the epitaxial source/drain region is disposed directly under the carbon-comprising gate spacer.