FinFET device and method of forming same
A method includes forming a fin over a substrate, forming a dummy gate structure over the fin, forming a first spacer over the dummy gate structure, implanting a first dopant in the fin to form a doped region of the fin adjacent the first spacer, removing the doped region of the fin to form a first recess, wherein the first recess is self-aligned to the doped region, and epitaxially growing a source/drain region in the first recess.
1. A method comprising:
forming a fin over a substrate;
forming a dummy gate structure over the fin;
forming a first spacer over the dummy gate structure;
implanting a first dopant in the fin to form a doped region of the fin adjacent the first spacer;
annealing the doped region of the fin;
after the annealing of the doped region of the fin, removing the doped region of the fin to form a first recess, wherein the sides of the first recess are aligned to the sides of the doped region; and
epitaxially growing a source/drain region in the first recess.
2. The method of claim 1 , wherein implanting the first dopant in the fin comprises a plasma doping process.
3. The method of claim 1 , wherein the first dopant is an N-type dopant.
4. The method of claim 3 , wherein the first dopant is arsenic.
5. The method of claim 1 , further comprising forming a second spacer over the first spacer.
6. The method of claim 5 , wherein the second spacer extends over the doped region.
7. The method of claim 1 , further comprising implanting a second dopant in the fin adjacent the dummy gate structure to form a lightly doped drain (LDD) region.
8. The method of claim 1 , wherein the doped region is removed using a plasma etch process.
9. A method comprising:
patterning a substrate to form a strip, the strip comprising a first semiconductor material;
forming an isolation region along a sidewall of the strip, an upper portion of the strip extending above a top surface of the isolation region;
forming a dummy gate structure along sidewalls and along a first top surface of the upper portion of the strip;
performing a first doping process to form a first doped region of the strip, the first doped region extending from a second top surface of the upper portion of the strip to below a top surface of the isolation region, the second top surface of the upper portion of the strip being adjacent the dummy gate structure;
forming a spacer along sidewalls of the dummy gate structure and over the first doped region;
performing a first etching process on the first doped region of the upper portion of the strip, wherein the first etching process selectively removes the portions of the strip comprising the first doped region to form a first recess; and
epitaxially growing a source/drain region in the first recess.
10. The method of claim 9 , wherein the first etching process etches the portions of the strip comprising the first doped region at a greater rate than the first etching process etches portions of the strip outside of the first doped region.
11. The method of claim 9 , wherein the first doping process further comprises performing an anneal process.
12. The method of claim 9 , wherein the first doping process comprises a plasma implant process.
13. The method of claim 9 , wherein the first doping process forms the first doped region by implanting arsenic.
14. The method of claim 9 , further comprising performing a second doping process to form a second doped region of the strip, wherein the second doping process is different than the first doping process.
15. A method comprising:
forming a first semiconductor fin over a substrate;
forming a gate stack overlying the first semiconductor fin;
forming a spacer on a sidewall of the gate stack;
doping the first semiconductor fin to form a first doped region, the first doped region extending under the spacer;
after forming the first doped region, doping the first semiconductor fin to form a second doped region, the second doped region extending below the first doped region;
etching the second doped region to form a recess in the first semiconductor fin, the recess extending under the spacer; and
growing an epitaxial region in the recess, the epitaxial region extending under the spacer, wherein the epitaxial region has a surface proximity measurement to tip proximity measurement difference of less than about 1%, wherein the surface proximity measurement is a lateral distance between a location at the middle of the gate stack and a sidewall of the epitaxial region at the top of the recess, and wherein the tip proximity measurement is a lateral distance between the location at the middle of the gate stack and a sidewall of the epitaxial region at half the depth of the recess.
16. The method of claim 15 , wherein forming the spacer comprises depositing an oxide layer on the sidewall of the gate stack and depositing a nitride layer over the oxide layer.
17. The method of claim 16 , wherein the epitaxial region extends completely under the nitride layer of the spacer.
18. The method of claim 15 , wherein doping the first semiconductor fin comprises using a plasma implant process to implant arsenic in the first semiconductor fin.
19. The method of claim 15 , further comprising annealing the second doped region.
20. The method of claim 15 , wherein the first doped region extends farther laterally under the spacer than the second doped region.