Method of fabricating gate structures

1. A method comprising:

providing a substrate;

forming first and second projections extending upwardly from the substrate, the projections having respective first and second channel regions therein;

forming a first structure engaging the first projection adjacent the first channel region, the first structure including:

a first dielectric material over the first channel region;

a non-metallic conductive layer over the first dielectric material; and

a first opening over the conductive layer;

forming a second structure engaging the second projection adjacent the second channel region, the second structure including:

a second dielectric material over the second channel region; and

a second opening larger than the first opening, the second opening being over the second dielectric material and the second channel region; and

conformally depositing a pure metal with a low resistivity in the first and second openings.

2. A method according to claim 1 , wherein the conformally depositing fills the first and second openings with the pure metal.

3. A method according to claim 1 , including heating the first structure to form a silicide from the metal in the first opening and at least a portion of the non-metallic conductive layer.

4. A method according to claim 1 ,

wherein the forming the first structure includes:

depositing the first dielectric material over the first channel region;

depositing the conductive layer over the first dielectric material;

forming a protection layer over the second structure; and

removing a portion of the conductive layer over the first channel region; and

wherein the forming the second structure includes:

depositing the second dielectric material over the second channel region;

depositing a dummy electrode over the second dielectric material;

forming a protection layer over the first structure; and

removing the dummy electrode.

5. A method according to claim 1 , wherein the conformally depositing includes selecting as the pure metal a metal with a band edge p-type work function value.

6. A method according to claim 5 , wherein the conformally depositing includes selecting as the pure metal one of cobalt (Co), nickel (Ni), and platinum (Pt).

7. A method according to claim 5 , wherein forming the first structure includes doping the non-metallic conductive layer to have an n-type work function value.

8. A method according to claim 1 ,

wherein the second channel region is a long channel region;

wherein the conformally depositing fills a portion of the second opening with the pure metal; and

including depositing a fill metal in a remaining portion of the second opening.

9. A method comprising:

providing a substrate;

forming first and second projections extending upwardly from the substrate, the projections having respective first and second channel regions therein;

forming a first structure engaging the first projection adjacent the first channel region, the first structure including:

a first dielectric material over the first channel region; and

a first opening over the first dielectric material and the first channel region;

forming a second structure engaging the second projection adjacent the second channel region, the second gate structure including:

a second dielectric material over the second channel region; and

a second opening over the second dielectric material and the second channel region;

conformally depositing a pure first metal with an n-type work function value and a low resistivity in the first opening; and

conformally depositing a pure second metal with a p-type work function value and a low resistivity in the second opening.

10. A method according to claim 9 ,

wherein the conformally depositing the pure first metal includes filling the first opening with the first metal; and

wherein the conformally depositing the pure second metal includes filling the second opening with the second metal.

11. A method according to claim 9 ,

wherein the forming the first structure includes:

depositing the first dielectric material over the first channel region;

depositing a first dummy electrode over the first dielectric material;

forming a protection layer over the second structure; and

removing the first dummy electrode; and

wherein the forming the second structure includes:

depositing the second dielectric material over the second channel region;

depositing a second dummy electrode over the second dielectric material;

forming a protection layer over the first structure; and

removing the second dummy electrode.

12. A method according to claim 9 , wherein the conformally depositing the pure first metal is carried out by depositing one of aluminum (Al) and tantalum (Ta).

13. A method according to claim 9 , wherein the conformally depositing the pure second metal is carried out by depositing one of cobalt (Co), nickel (Ni), and platinum (Pt).

14. A method according to claim 9 ,

wherein the first and second channel regions are long channel regions;

wherein the conformally depositing the pure first metal fills a portion of the first opening;

wherein the conformally depositing the pure second metal fills a portion of the second opening; and

including depositing a fill metal in remaining portions of the first and second openings.