Selective growth for high-aspect ratio metal fill
An improved conductive feature for a semiconductor device and a technique for forming the feature are provided. In an exemplary embodiment, the semiconductor device includes a substrate having a gate structure formed thereupon. The gate structure includes a gate dielectric layer disposed on the substrate, a growth control material disposed on a side surface of the gate structure, and a gate electrode fill material disposed on the growth control material. The gate electrode fill material is also disposed on a bottom surface of the gate structure that is free of the growth control material. In some such embodiments, the gate electrode fill material contacts a first surface and a second surface that are different in composition.
1. A device comprising:
a fin structure disposed on a substrate;
a gate structure disposed over the fin structure, wherein the gate structure includes:
a gate dielectric layer disposed over the fin structure;
a first layer disposed over the gate dielectric layer, the first layer having a first sidewall and a second opposing sidewall such that a bottom surface of the first layer extends from the first sidewall to the second sidewall of the first layer;
a growth control material disposed along and physically contacting the first sidewall of the first layer, the growth control material having a different material composition than the first layer, the growth control material having the same material composition throughout the growth control material; and
a gate electrode fill material disposed on and physically contacting the growth control material and physically contacting the bottom surface of the first layer, the gate electrode fill material having a different material composition than the growth control material.
2. The device of claim 1 , wherein the first layer includes a material selected from the group consisting of a metal oxide and a metal nitride.
3. The device of claim 1 , wherein the gate electrode fill material is disposed between the growth control material and the bottom surface of the first layer such that no portion of the growth control material interfaces with the bottom surface of the first layer.
4. The device of claim 1 , wherein the growth control material extends to and physically contacts the bottom surface of the first layer.
5. The device of claim 1 , wherein the gate structure further includes a work function layer disposed on the gate dielectric layer such that the work function layer is disposed between the gate dielectric layer and the first layer.
6. The device of claim 5 , wherein the gate structure further includes a wetting layer disposed on the work function layer such that the wetting layer is disposed between the work function layer and the first layer.
7. The device of claim 1 , wherein the growth control material includes a material selected from the group consisting of WC, WN, AlC, and AlN.
8. A device comprising:
a gate structure disposed over a substrate, wherein the gate structure includes:
a first material layer having a first u-shaped profile defining a recess, the first material layer having a bottom surface;
a growth control material disposed within the recess, the growth control material decreasing in thickness as the growth control material extends towards the substrate, the growth control material having a different material composition than the first material layer, the growth control material having the same material composition throughout the growth control material; and
a fill material disposed within the recess and physically contacting the growth control material and the bottom surface of the first material layer, the fill material having a different material composition than the growth control material.
9. The device of claim 8 , wherein the gate structure further includes:
a gate dielectric layer having a second u-shaped profile;
a work function layer having a third u-shaped profile;
a wetting layer having a fourth u-shaped profile, and
wherein the first material layer is barrier layer.
10. The device of claim 9 , wherein the gate dielectric layer, the work function layer, the wetting layer, and the barrier layer are formed of different materials.
11. The device of claim 8 , wherein the growth control material extends to and physically contacts the bottom surface of the first material layer.
12. The device of claim 8 , wherein the growth control material does not physically contact the bottom surface of the first material layer.
13. The device of claim 8 , wherein the first material layer, the growth control material and the fill material extend to the same height over the substrate.
14. The device of claim 8 , wherein the first material layer includes an oxide material.
15. A device comprising:
a gate structure disposed over a semiconductor substrate, wherein the gate structure includes:
a gate dielectric layer disposed over the semiconductor substrate;
a barrier layer disposed over the gate dielectric layer, the barrier layer having a first sidewall and a second opposing sidewall such that a bottom surface of the barrier layer extends from the first sidewall to the second sidewall of the barrier layer;
a growth control material disposed along and physically contacting the first sidewall of the barrier layer, the growth control material having a different material composition than the barrier layer, the growth control material having the same material composition throughout the growth control material; and
a gate electrode fill material disposed on the growth control material and disposed directly on a first portion of the bottom surface of the barrier layer, the gate electrode fill material having a different material composition than the growth control material.
16. The device of claim 15 , wherein the growth control material is disposed directly on a second portion of the bottom surface of the barrier layer.
17. The device of claim 15 , wherein the gate electrode fill material has a first width along an upper portion of the gate structure and a second width along a lower portion of the gate structure, the first width being different than the second width.
18. The device of claim 15 , wherein the gate structure further includes:
a work function metal layer disposed directly on the gate dielectric layer; and
a wetting layer disposed directly on the work function metal layer.
19. The device of claim 18 , wherein the barrier layer is disposed directly on the wetting layer.
20. The device of claim 15 , wherein the width of the growth control material decreases as the growth control material extends along the first sidewall of the barrier layer toward the bottom surface of the barrier layer.