Capacitor structure and fabrication method thereof
A capacitor structure includes a substrate having thereon a storage node contact, a cylinder-shaped bottom electrode disposed on the storage node contact, a supporting structure horizontally supporting a sidewall of the cylinder-shaped bottom electrode, a capacitor dielectric layer conformally covering the cylinder-shaped bottom electrode and the supporting structure, and a top electrode covering the capacitor dielectric layer. The supporting structure has a top surface that is higher than that of the cylinder-shaped bottom electrode. The top surface of the supporting structure has a V-shaped sectional profile.
1. A capacitor structure, comprising:
a substrate having thereon a storage node contact;
a cylinder-shaped bottom electrode disposed on the storage node contact;
a supporting structure horizontally supporting a sidewall of the cylinder-shaped bottom electrode, wherein the supporting structure has a top surface that is higher than an uppermost point of the cylinder-shaped bottom electrode, and wherein the top surface of the supporting structure has a V-shaped sectional profile;
a capacitor dielectric layer conformally covering the cylinder-shaped bottom electrode and the supporting structure; and
a top electrode covering the capacitor dielectric layer.
2. The capacitor structure according to claim 1 , wherein the supporting structure is in direct contact with the sidewall of the cylinder-shaped bottom electrode.
3. The capacitor structure according to claim 1 , wherein the supporting structure comprises an oblique sidewall extending downwardly to a top surface of the cylinder-shaped bottom electrode.
4. The capacitor structure according to claim 3 , wherein the supporting structure comprises SiN or SiCN.
5. The capacitor structure according to claim 4 , wherein the cylinder-shaped bottom electrode comprises TiN.
6. The capacitor structure according to claim 5 further comprising:
a first protective layer on the oblique sidewall of the supporting structure; and
a second protective layer on the cylinder-shaped bottom electrode.
7. The capacitor structure according to claim 6 , wherein the first protective layer comprises SiON or SiOCN.
8. The capacitor structure according to claim 6 , wherein the second protective layer comprises TiO 2 .
9. A method for forming a capacitor structure, comprising:
providing a substrate having thereon a storage node contact;
forming a cylinder-shaped bottom electrode on the storage node contact;
forming a supporting structure horizontally supporting a sidewall of the cylinder-shaped bottom electrode;
forming a capacitor dielectric layer over the cylinder-shaped bottom electrode and the supporting structure, wherein the supporting structure has a top surface that is higher than an uppermost point of the cylinder-shaped bottom electrode, and wherein the top surface of the supporting structure has a V-shaped indentation; and
forming a top electrode over the capacitor dielectric layer.
10. The method according to claim 9 , wherein the supporting structure is in direct contact with the sidewall of the cylinder-shaped bottom electrode.
11. The method according to claim 9 , wherein the supporting structure comprises an oblique sidewall extending downwardly to a top surface of the cylinder-shaped bottom electrode.
12. The method according to claim 11 , wherein the supporting structure comprises SiN or SiCN.
13. The method according to claim 12 , wherein the cylinder-shaped bottom electrode comprises TiN.
14. The method according to claim 13 further comprising:
forming a first protective layer on the oblique sidewall of the supporting structure; and
forming a second protective layer on the cylinder-shaped bottom electrode.
15. The method according to claim 14 , wherein the first protective layer comprises SiON or SiOCN.
16. The method according to claim 14 , wherein the second protective layer comprises TiO 2 .
17. The method according to claim 9 , wherein the step of forming a supporting structure further comprising performing a O 2 treatment and a Cl 2 etch to form the V-shaped indentation on the top surface of the supporting structure.
18. The method according to claim 11 , wherein the step of forming a supporting structure further comprising performing a O 2 treatment and a Cl 2 etch to form the oblique sidewall extending downwardly to a top surface of the cylinder-shaped bottom electrode.