FinFETs with controllable and adjustable channel doping
A method of forming features of a finFET structure includes forming fins on a surface of a substrate. A first liner is formed around each fin and a shallow trench isolation region is formed around each fin. A dopant layer is implanted in each fin. A portion of the shallow trench isolation region is etched from each fin. A first portion of the structure is blocked and the first liner replaced with a second liner in a second portion of the structure.
1. A finFET structure, comprising:
a plurality of fins located on a surface of a substrate;
a first liner disposed around each fin in a high threshold voltage region of the structure, with a dopant layer implanted into each fin; and
a second liner disposed around each fin in a low threshold voltage region of the structure, with a dopant layer implanted into each fin;
wherein the first liner and the second liner comprise different materials, and the second liner is used to control and adjust channel doping for the fin.
2. The finFET structure of claim 1 , wherein the first liner comprises a material selected from nitride, nitride oxide, or a combination comprising at least one of the foregoing.
3. The finFET structure of claim 1 , wherein the first liner comprises a nitride.
4. The finFET structure of claim 1 , wherein the second liner comprises an oxide.
5. The finFET structure of claim 3 , wherein the second liner comprises silicon dioxide.
6. The finFET structure of claim 1 , wherein an upper portion of the fins in the first region comprise a substantially low concentration of dopants from the dopant layer.
7. The finFET structure of claim 5 , wherein the substantially low concentration of dopants is less than or equal to 1×10 17 /(cm 3 ) dopants.
8. The finFET structure of claim 1 , wherein the first liner comprises a nitride, and the second liner comprises an oxide.
9. The finFET structure of claim 1 further comprising a gate stack arranged on the fin.
10. A finFET structure, comprising:
a fin located on a surface of a substrate;
a first liner disposed around a portion of the fin arranged within a shallow trench isolation region;
a second liner disposed around another portion of the fin over the shallow trench isolation region; and
a dopant layer implanted into the fin;
wherein the first liner and the second liner comprise different materials, and the second liner is used to control and adjust channel doping for the fin.
11. The finFET structure of claim 10 , wherein the first liner comprises a material selected from nitride, nitride oxide, or a combination comprising at least one of the foregoing.
12. The finFET structure of claim 10 , wherein the first liner comprises a nitride.
13. The finFET structure of claim 10 , wherein the second liner comprises an oxide.
14. The finFET structure of claim 12 , wherein the second liner comprises silicon dioxide.
15. The finFET structure of claim 10 , wherein an upper portion of the fins in the first region comprise a substantially low concentration of dopants from the dopant layer.
16. The finFET structure of claim 14 , wherein the substantially low concentration of dopants is less than or equal to 1×10 17 /(cm 3 ) dopants.
17. The finFET structure of claim 10 , wherein the first liner comprises a nitride, and the second liner comprises an oxide.
18. The finFET structure of claim 10 further comprising a gate stack arranged on the fin.