Fin field effect transistor structure and method to form defect free merged source and drain epitaxy for low external resistance
A method of forming a semiconductor device that includes providing a plurality of fin structures, wherein a surface of the fin structures has a first orientation for a diamond shaped epitaxial growth deposition surface. A first epitaxial semiconductor material having a diamond geometry is grown on the diamond shaped epitaxial growth surface. A blocking material is formed protecting a lower portion of the first epitaxial semiconductor material. An upper portion of the first epitaxial semiconductor material is removed to expose a second orientation surface of the first epitaxial semiconductor material for merged epitaxial semiconductor growth. A second epitaxial semiconductor material is epitaxially formed on the first epitaxial semiconductor material. The second epitaxial semiconductor material has a substantially planar upper surface and extends into direct contact with at least two adjacent fin structures.
1. A method of forming a semiconductor device comprising:
forming a blocking material protecting a lower portion of a first epitaxial semiconductor material having a diamond geometry on a plurality of fin structures and leaving an upper portion of the first epitaxial semiconductor material exposed;
removing an apex portion of the first epitaxial semiconductor material to expose a second orientation surface of the first epitaxial semiconductor material having a planar upper surface for merged epitaxial semiconductor growth, wherein an entirety of sidewalls of the first epitaxial semiconductor material tapers with a decreasing width dimension in a direction extending from the planar upper surface to a base of the first epitaxial semiconductor material; and
epitaxially forming a second epitaxial semiconductor material on the first epitaxial semiconductor material, the second epitaxial semiconductor material having a rectangular geometry and extending into contact with at least two adjacent fin structures of said plurality of fin structures.
2. The method of claim 1 , further comprising forming a sacrificial gate structure on a channel region portion of the fin structures before forming said first epitaxial semiconductor material.
3. The method of claim 2 , further comprising substituting the sacrificial gate structure with a functional gate structure after forming the second epitaxial semiconductor material.
4. The method of claim 1 , wherein the diamond geometry is formed on an epitaxial growth surface comprising a (110) surface.
5. The method of claim 1 , wherein the first epitaxial semiconductor material having the diamond geometry is non merged epitaxial semiconductor material.
6. The method of claim 1 , wherein said forming the blocking material protecting the lower portion of the first epitaxial semiconductor material comprises depositing the blocking material to a height below a sidewall apex of the first epitaxial semiconductor material having the diamond geometry.
7. The method of claim 1 , wherein said removing the upper portion of the first epitaxial semiconductor material to expose the second orientation surface of the first epitaxial semiconductor material for merged epitaxial semiconductor growth comprises an anisotropic etch.
8. The method of claim 1 , wherein the second orientation surface is a (100) crystal plane.
9. A method of forming a semiconductor device comprising:
removing an apex portion of a first epitaxial semiconductor material having a diamond geometry that is present on a plurality of fin structures to expose a second orientation surface of the first epitaxial semiconductor material having a planar upper surface for merged epitaxial semiconductor growth, wherein an entirety of sidewalls of the first epitaxial semiconductor material tapers with a decreasing width dimension in a direction extending from the planar upper surface to a base of the first epitaxial semiconductor material; and
epitaxially forming a second epitaxial semiconductor material on the first epitaxial semiconductor material, the second epitaxial semiconductor material having a rectangular geometry and extending into contact with at least two adjacent fin structures of said plurality of fin structures.
10. The method of claim 9 , further comprising forming a sacrificial gate structure on a channel region portion of the fin structures before forming said first epitaxial semiconductor material.
11. The method of claim 10 , further comprising substituting the sacrificial gate structure with a functional gate structure after forming the second epitaxial semiconductor material.
12. The method of claim 9 , wherein the diamond geometry is formed on an epitaxial growth surface comprising a (110) surface.
13. The method of claim 9 , wherein the first epitaxial semiconductor material having the diamond geometry is non merged epitaxial semiconductor material.
14. The method of claim 9 , wherein said removing the apex portion of the first epitaxial semiconductor material having the diamond geometry comprises depositing a blocking material protecting a lower portion of the first epitaxial semiconductor material.
15. The method of claim 14 , wherein said depositing the blocking material protecting the lower portion of the first epitaxial semiconductor material comprises depositing the blocking material to a height below a sidewall apex of the first epitaxial semiconductor material having the diamond geometry.
16. The method of claim 15 , wherein said removing the upper portion of the first epitaxial semiconductor material to expose the second orientation surface of the first epitaxial semiconductor material for merged epitaxial semiconductor growth comprises an anisotropic etch.
17. The method of claim 16 , wherein the second orientation surface is a (100) crystal plane.