Vertical tunneling field-effect transistor cell

1. A semiconductor device comprising:

a substrate;

a protrusion structure disposed over the substrate and protruding out of the plane of substrate;

a gate stack disposed over the substrate, wherein the gate stack includes a planar portion, which is symmetrically to the protrusion structure and parallel to the surface of substrate and a gating surface, which wraps around a middle portion of the protrusion structure; and

a source region disposed as a top portion of the protrusion structure, including overlapping with a top portion of the gating surface of the gate stack;

a drain region disposed over the substrate symmetrically adjacent to the protrusion structure and extending to a bottom portion of the protrusion structure as a raised drain region;

a source contact disposed on the source region;

a gate contact disposed on the planar portion of the gate stack;

a drain contact disposed on the drain region; and

the source contact aligns with other two source contacts of two adjacent semiconductor devices such that each source contact locates in one of three angles of an equilateral triangle.

2. The semiconductor device of claim 1 , wherein the protrusion structure includes a cylinder structure.

3. The semiconductor device of claim 1 , wherein gate contacts and drain contacts align symmetrically along two straight lines which are perpendicular to each other.

4. The semiconductor device of claim 3 , wherein there are at least one of four gate contacts and one of four drain contacts, which are symmetrically positioned in the planar portion of the gate stack and the drain region.

5. The semiconductor device of claim 1 , wherein the gate contacts symmetrically along two lines which are perpendicular to each other and the drain contacts symmetrically along another two lines which are perpendicular to each other, further wherein the gate contact has a 45 degree angle to nearest respective drain contact.

6. The semiconductor device of claim 1 , wherein the gate contacts and drain contacts align symmetrically along three straight lines, each intersecting at a common point, and directed 60 degrees from each other.

7. The semiconductor device of claim 6 , wherein there are at least one of six gate contacts and one of six drain contacts, which are symmetrically positioned in the planar portion of the gate stack and the drain region.

8. The semiconductor device of claim 1 , wherein the gate contacts symmetrically along three straight lines, each intersecting at a common point and directed 60 degrees from each other and the drain contacts symmetrically along another three straight lines, each intersecting at a common point and directed 60 degrees from each other, further wherein the gate contact has a 30 degree angle to nearest respective drain contact.

9. The semiconductor device of claim 1 , wherein the protrusion structure includes a regular hexagonal-column structure.

10. The semiconductor device of claim 1 , wherein the protrusion structure includes an oval-cylinder structure.

11. The semiconductor device of claim 1 , wherein the protrusion structure includes a square-column structure.

12. The semiconductor device of claim 1 , further comprising:

an isolation feature disposed between each drain region; and

an isolation dielectric layer disposed over the substrate, including between the drain region and the planar portion of the gate stack.

13. A semiconductor device comprising:

a semiconductor substrate;

a cylinder shape protrusion disposed over the substrate and protruding out of the plane of semiconductor substrate;

a source region at a top portion of the protrusion;

a high-k/metal gate (HK/MG) disposed over the semiconductor substrate, wherein the HK/MG having a planar portion, which is symmetrically to the cylinder protrusion and parallel to the surface of semiconductor substrate and a gating surface, which wraps around a middle portion of the cylinder protrusion, including overlapping with the source region;

a drain region disposed over the semiconductor substrate symmetrically adjacent to the cylinder protrusion and extending to a bottom portion of the cylinder protrusion as a raised drain region;

an isolation dielectric layer disposed between the planar portion of the HK/MG and the drain region, over the source region and the drain region;

a source contact disposed at the source region;

a gate contact aligns to the cylinder protrusion;

a drain contact disposed at the drain region; and

the source contact aligns with other two source contacts of two adjacent semiconductor devices such that each source contact locates in one of three angles of an equilateral triangle.

14. The semiconductor device of claim 13 , wherein the gate contacts and drain contacts align symmetrically along two straight lines which are perpendicular to each other.

15. The semiconductor device of claim 13 , wherein the gate contacts symmetrically along two lines which are perpendicular to each other and the drain contacts symmetrically along another two lines which are perpendicular to each other, further wherein the gate contact has a 45 degree angle to nearest respective drain contact.

16. The semiconductor device of claim 13 , wherein gate contacts and drain contacts align symmetrically along three straight lines which two adjacent line having 60 degree to each other.

17. The semiconductor device of claim 13 , wherein the gate contacts symmetrically along three straight lines, each intersecting at a common point and directed 60 degrees from each other and the drain contacts symmetrically along another three straight lines, each intersecting at a common point and directed 60 degrees from each other, further wherein the gate contact has a 30 degree angle to nearest respective drain contact.

18. A semiconductor device comprising:

first, second and third cylinder-shaped tunneling field-effect transistors (TFETs), each TFET having:

a source contact;

a gate contact; and

a drain contact

wherein the source contact of the first cylinder-shape TFET aligns with the source contacts of the second and third cylinder-shape TFET such that each source contact is located at a vertex of an equilateral triangle; and

wherein the gate contacts and drain contacts of the three TFETS align symmetrically with each other along more than one straight line.

19. The semiconductor device of claim 18 , wherein a plurality of gate and drain contacts align symmetrically along straight lines, each intersecting at a common point and directed a fixed angle from each other, wherein gate contacts align to respective drain contacts.

20. The semiconductor device of claim 18 , wherein a plurality of gate and drain contacts align symmetrically along straight lines, each intersecting at a common point and directed a fixed angle from each other, wherein gate contacts align to a different line than drain contact align to.