Transistor gate having tapered segments positioned above the fin channel

1. A method of forming an integrated circuit (IC) structure, the method comprising:

forming a fin over a major surface of a substrate;

wherein the fin comprises an active fin region having a top fin surface and a fin sidewall;

wherein the top fin surface is substantially parallel with respect to the major surface of the substrate;

wherein the fin sidewall is substantially perpendicular with respect to the major surface of the substrate;

forming a gate over and around a central portion of the fin, the gate having a bottom gate region and a top gate region;

wherein the bottom gate region is substantially below the top fin surface and includes a bottom gate region sidewall that is substantially parallel with respect to the fin sidewall and substantially perpendicular with respect to the major surface of the substrate; and

wherein the top gate region is substantially above the top fin surface and includes a top gate region sidewall that is substantially planar, substantially non-parallel with respect to the fin sidewall, and substantially non-parallel with respect to the major surface of the substrate.

2. The method of claim 1 , wherein forming the gate comprises:

forming a gate trench over and around the central portion of the fin, the gate trench comprising a bottom gate trench and a top gate trench;

wherein the bottom gate trench is substantially below the top fin surface and comprises a bottom gate trench sidewall that is substantially parallel with respect to the fin sidewall and substantially perpendicular with respect to the major surface of the substrate;

wherein the top gate trench is substantially above the top fin surface and comprises a top gate trench sidewall that is substantially planar, substantially non-parallel with respect to the fin sidewall, and substantially non-parallel with respect to the major surface of the substrate; and

forming the gate within the gate trench;

wherein the bottom gate trench defines the bottom gate region to be substantially below the top fin surface and to include the bottom gate region sidewall that is substantially parallel with respect to the fin sidewall and substantially perpendicular with respect to the major surface of the substrate; and

wherein the top gate trench defines the top gate region to be substantially above the top fin surface and to include the top gate region sidewall that is substantially planar, substantially non-parallel with respect to the fin sidewall, and substantially non-parallel with respect to the major surface of the substrate.

3. The method of claim 2 , wherein forming the gate within the gate trench comprises:

forming a dummy gate within the gate trench; and

replacing the dummy gate with a conductive material.

4. The method of claim 3 , wherein forming the gate trench comprises:

depositing a dummy fill material over the active region of the fin;

forming a precursor gate trench in the dummy fill material; and

forming a gate spacer within a portion of the precursor gate trench.

5. The method of claim 4 wherein:

the precursor gate trench comprises a bottom precursor gate trench and a top precursor gate trench;

the bottom precursor gate trench is substantially below the top fin surface;

the top precursor gate trench is substantially above the top fin surface; and

the gate spacer comprises a top gate spacer region and a bottom gate spacer region.

6. The method of claim 5 , wherein forming the gate trench further comprises:

depositing the bottom gate spacer region on a sidewall of the bottom precursor gate trench such that a sidewall of the bottom gate spacer region is exposed;

depositing the top gate spacer region on a sidewall of the top precursor gate trench such that a sidewall of the top gate spacer region is exposed;

wherein the bottom gate trench sidewall comprises the exposed sidewall of the bottom gate spacer region; and

wherein the top gate trench sidewall comprises the exposed sidewall of the top gate spacer region.

7. The method of claim 6 , wherein forming the gate within the gate trench comprises:

forming a dummy gate within the gate trench;

removing the dummy fill material; and

replacing the dummy gate with a conductive material.

8. The method of claim 7 , wherein forming dummy gate is subsequent to forming the gate spacer.

9. A method of forming an integrated circuit (IC) structure, the method comprising:

forming a fin over a major surface of a substrate;

wherein the fin comprises an active fin region having a top fin surface and a fin sidewall;

wherein the top fin surface is substantially parallel with respect to the major surface of the substrate;

wherein the fin sidewall is substantially perpendicular with respect to the major surface of the substrate;

forming a gate over and around a central portion of the fin, the gate having a bottom gate region and a top gate region;

wherein the bottom gate region is substantially below the top fin surface; and

wherein the top gate region is substantially above the top fin surface and includes a top gate region sidewall that is substantially planar, substantially non-parallel with respect to the fin sidewall, and substantially non-parallel with respect to the major surface of the substrate.

10. The method of claim 9 , wherein forming the gate comprises:

forming a gate trench over and around the central portion of the fin, the gate trench comprising a bottom gate trench and a top gate trench;

wherein the bottom gate trench is substantially below the top fin surface and comprises a bottom gate trench sidewall that is substantially parallel with respect to the fin sidewall and substantially perpendicular with respect to the major surface of the substrate;

wherein the top gate trench is substantially above the top fin surface; and

forming the gate within the gate trench;

wherein the bottom gate trench defines the bottom gate region to be substantially below the top fin surface and to include the bottom gate region sidewall that is substantially parallel with respect to the fin sidewall and substantially perpendicular with respect to the major surface of the substrate; and

wherein the top gate trench and the top gate trench sidewall define the top gate region to be substantially above the top fin surface and to include the top gate region sidewall that is substantially planar, substantially non-parallel with respect to the fin sidewall, and substantially non-parallel with respect to the major surface of the substrate.

11. The method of claim 10 , wherein forming the gate further comprises:

forming a dummy gate within the gate trench; and

replacing the dummy gate with a conductive material.

12. The method of claim 10 , wherein forming the gate trench further comprises:

depositing a dummy fill material over the active region of the fin;

forming a precursor gate trench in the dummy fill material; and

forming a gate spacer within a portion of the precursor gate trench.

13. The method of claim 12 wherein:

the precursor gate trench comprises a bottom precursor gate trench and a top precursor gate trench;

the bottom precursor gate trench is substantially below the top fin surface;

the top precursor gate trench is substantially above the top fin surface; and

the gate spacer comprises a top gate spacer region and a bottom gate spacer region.

14. The method of claim 13 , wherein forming the gate trench further comprises:

depositing the bottom gate spacer region on a sidewall of the bottom precursor gate trench such that a sidewall of the bottom gate spacer region is exposed;

depositing the top gate spacer region on a sidewall of the top precursor gate trench such that a sidewall of the top gate spacer region is exposed;

wherein the bottom gate trench sidewall comprises the exposed sidewall of the bottom gate spacer region; and

wherein the top gate trench sidewall comprises the exposed sidewall of the top gate spacer region.

15. The method of claim 14 , wherein forming the gate further comprises:

forming a dummy gate within the gate trench;

removing the dummy fill material; and

replacing the dummy gate with a conductive gate material.

16. The method of claim 15 , wherein forming the dummy gate is subsequent to forming the gate spacer.

17. An integrated circuit (IC) structure comprising:

a fin formed over a major surface of a substrate;

wherein the fin comprises an active fin region having a top fin surface and a fin sidewall;

wherein the top fin surface is substantially parallel with respect to the major surface of the substrate;

wherein the fin sidewall is substantially perpendicular with respect to the major surface of the substrate; and

a gate formed over and around a central portion of the fin, the gate having a bottom gate region and a top gate region;

wherein the bottom gate region is substantially below the top fin surface and includes a bottom gate region sidewall that is substantially parallel with respect to the fin sidewall and substantially perpendicular with respect to the major surface of the substrate; and

wherein the top gate region is substantially above the top fin surface and includes a top gate region sidewall that is substantially planar, substantially non-parallel with respect to the fin sidewall, and substantially non-parallel with respect to the major surface of the substrate.

18. The structure of claim 17 further comprising a gate spacer adjacent to the gate, the gate spacer having a top gate spacer region and a bottom gate spacer region.

19. The structure of claim 18 , wherein a sidewall of the bottom gate spacer region is adjacent to the bottom gate region sidewall, substantially parallel with respect to the fin sidewall, and substantially perpendicular with respect to the major surface of the substrate.

20. The structure of claim 19 , wherein a sidewall of the top gate spacer region is adjacent to the top gate region sidewall, substantially non-parallel with respect to the fin sidewall, and substantially non-parallel with respect to the major surface of the substrate.