Eliminating shorting between ferroelectric capacitors and metal contacts during ferroelectric random access memory fabrication
Disclosed herein is an apparatus that includes a ferrocapacitor having a sidewall. An etch stopping film is disposed along the sidewall of the ferrocapacitor, with a hydrogen barrier film disposed between the etch stopping film and the sidewall of the ferrocapacitor.
1. An apparatus comprising:
a first ferrocapacitor having a first sidewall;
a hydrogen barrier film disposed along the first sidewall of the first ferrocapacitor, the hydrogen barrier film having an outer surface and an inner surface, wherein the inner surface of the hydrogen barrier film is in contact with the first sidewall of the ferrocapacitor; and
an etch stopping film disposed along the outer surface of the hydrogen barrier film,
wherein the etch stopping film comprises titanium aluminum oxy-nitride (TiAlON), and wherein a nitrogen to oxygen ratio varies along a direction from an inner surface of the etch stopping film to an outer surface of the etch stopping film.
2. The apparatus of claim 1 , wherein the etch stopping film comprises at least one of silicon nitride (SiN), silicon oxy-nitride (SiON), titanium oxy-nitride (TiON), or titanium aluminum oxy-nitride (TiAlON).
3. The apparatus of claim 1 , wherein a thickness of the etch stopping film is between 10 nanometers and 100 nanometers.
4. The apparatus of claim 1 , wherein the first ferrocapacitor is disposed within a dielectric material.
5. The apparatus of claim 4 , wherein a first etch rate of the etch stopping film is less than a second etch rate of the dielectric material.
6. The apparatus of claim 5 , wherein a ratio of the second etch rate of the dielectric material to the first etch rate of the etch stopping film is between 2 and 15.
7. The apparatus of claim 1 , wherein a first portion of the hydrogen barrier film is disposed along an upper surface of the ferrocapacitor, and a second portion of the etch stopping film is disposed along the first portion of the hydrogen barrier film which is disposed along the upper surface of the ferrocapacitor.
8. The apparatus of claim 1 , further comprising a metal contact disposed adjacent to the first ferrocapacitor and separated from the first ferrocapacitor by a dielectric material, wherein a minimum distance between the first sidewall of the first ferrocapacitor and an edge of the metal contact is between 20 nanometers and 120 nanometers.
9. The apparatus of claim 8 , wherein the minimum distance is about equal to a combined thickness of the hydrogen barrier film and the etch stopping film.
10. The apparatus of claim 1 , wherein a first lower surface of the first ferrocapacitor is disposed along a dielectric layer.
11. The apparatus of claim 10 , further comprising:
a second ferrocapacitor having a second sidewall and a second lower surface, wherein the second lower surface of the second ferrocapacitor is disposed along the dielectric layer; and
a metal contact disposed between the first sidewall of the first ferrocapacitor and the second sidewall of the second ferrocapacitor, wherein a minimum distance between the first sidewall of the first ferrocapacitor and the second sidewall of the second ferrocapacitor is between 100 nanometers and 425 nanometers.
12. The apparatus of claim 1 , wherein the hydrogen barrier film comprises two or more layers.
13. The apparatus of claim 1 , wherein the etch stopping film comprises two or more layers.
14. An apparatus comprising:
a memory, the memory comprising:
a first ferrocapacitor having a sidewall;
a hydrogen barrier film disposed along the sidewall of the first ferrocapacitor, the hydrogen barrier film having an outer surface and an inner surface, wherein the inner surface of the hydrogen barrier film is in contact with the sidewall of the ferrocapacitor; and
an etch stopping film disposed along the outer surface of the hydrogen barrier film,
wherein the etch stopping film comprises an oxy-nitride and wherein a nitrogen to oxygen ratio varies along a direction from an inner surface of the etch stopping film to an outer surface of the etch stopping film.
15. The apparatus of claim 14 , wherein the memory is a ferroelectric random-access memory (PRAM).
16. The apparatus of claim 14 , wherein the oxy-nitride of the etch stopping film comprises titanium aluminum oxy-nitride (TiAlON).
17. An apparatus comprising:
a ferrocapacitor formed on a substrate, the ferrocapacitor having a sidewall and an upper surface;
a hydrogen barrier film disposed on the sidewall and upper surface of the ferrocapacitor and on a surface of the substrate;
an etch stopping film disposed on an outer surface of the hydrogen barrier film overlying the sidewall of the ferrocapacitor;
an interlevel dielectric (ILD) disposed over the ferrocapacitor covering the hydrogen barrier film, etch stopping film and surface of the substrate; and
a first metal contact formed in a first contact opening extending through the ILD and the hydrogen barrier film to a lower metal contact formed on the surface of the substrate,
wherein the first contact opening exposes but does not extend through the etch stopping film covering the outer surface of the hydrogen barrier film overlying the sidewall of the ferrocapacitor.
18. The apparatus of claim 17 , wherein the etch stopping film is further disposed on a first portion of the upper surface of the ferrocapacitor, and further comprising a second metal contact formed in a second contact opening extending through the ILD and the hydrogen barrier film to the upper surface of the ferrocapacitor not covered by the etch stopping film,
wherein the second contact opening exposes but does not extend through the etch stopping film covering the first portion of the upper surface of the ferrocapacitor.
19. The apparatus of claim 17 , wherein the etch stopping film comprises titanium aluminum oxy-nitride (TiAlON), and wherein a nitrogen to oxygen ratio varies along a direction from an inner surface of the etch stopping film to an outer surface of the etch stopping film.