Ferroelectric capacitor and integrated circuit device comprising same

Claims

What is claimed is:

1. An integrated circuit device comprising:

a substrate;

a first capacitor plate formed on the substrate;

a layer of ferroelectric material formed on the first capacitor plate;

a second capacitor plate formed over part of the ferroelectric material; and

a graded diffusion barrier material deposited over the second capacitor plate and an exposed part of the ferroelectric material.

2. The device of claim 1 wherein:

the ferroelectric material comprises a material selected from the group consisting of PbZrTiO.sub.3 and SrBi.sub.2 Ta.sub.2 O.sub.9.

3. The device of claim 1 wherein:

the diffusion barrier layer material comprises a material selected from the group consisting of TiO.sub.2, ZrO.sub.2, Ta.sub.2 O.sub.5, Nb.sub.2 O.sub.5, Zr.sub.1-x Ti.sub.x O.sub.2, where x is a number in a range from zero to one, and Ta.sub.5-y Si.sub.y O.sub.10, where y is a number in a range from zero to five.

4. The device of claim 1 wherein:

the insulative layer material comprises SiO.sub.2.

5. The device of claim 1, further comprising an insulative material deposited over the diffusion barrier material, wherein:

the insulative layer material comprises a material selected from the group consisting of Si.sub.3 N.sub.4, spin-on-glass, SiF.sub.z O.sub.4-z, and organic dielectric materials, where z is a number in a range from zero to four.

6. The device of claim 1, further comprising an insulative material deposited over the diffusion barrier material, wherein:

the diffusion barrier material comprises a material selected from the group consisting of TiO.sub.2, ZrO.sub.2, Ta.sub.2 O.sub.5, and Nb.sub.2 O.sub.5.

7. The device of claim 1 wherein the ferroelectric material comprises lead zirconium titanate.

8. The device of claim 1 wherein the ferroelectric material comprises strontium bismuth tantalate.

9. The device of claim 1 wherein the diffusion barrier material comprises titanium oxide.

10. The device of claim 1 wherein the diffusion barrier material comprises zirconium oxide.

11. The device of claim 1 wherein the diffusion barrier material comprises tantalum oxide.

12. The device of claim 1 wherein the diffusion barrier material comprises niobium oxide.

13. The device of claim 1, further comprising an insulative material deposited over the diffusion barrier material, wherein the insulative material comprises silicon nitride.

14. The device of claim 1, further comprising an insulative material deposited over the diffusion barrier material, wherein the insulative material comprises spin-on-glass.

15. The device of claim 1, further comprising an insulative material deposited over the diffusion barrier material, wherein the insulative material comprises silicon fluoride.

16. The device of claim 1, further comprising an insulative material deposited over the diffusion barrier material, wherein the insulative material comprises an organic dielectric material.

17. The device of claim 1, further comprising an insulative material deposited over the diffusion barrier material, wherein the insulative material comprises polyimide.

18. The device of claim 1 wherein the first capacitor plate is formed of a metal selected from the group consisting of aluminum, copper and tungsten.

19. The device of claim 1 wherein the first capacitor plate is formed of a material comprising aluminum.

20. The device of claim 1 wherein the first capacitor plate is formed of a material comprising copper.

21. The device of claim 1 wherein the first capacitor plate is formed of a material comprising tungsten.

22. The device of claim 1, further comprising an insulative material deposited over the diffusion barrier material, wherein the ferroelectric material comprises an oxide material selected from the group consisting of lead zirconium titanate and strontium bismuth tantalate, wherein the oxygen diffusion barrier layer comprises an oxide selected from the group consisting of titanium oxide, zirconium oxide, tantalum oxide and niobium oxide, and wherein the insulative material comprises a material selected from the group consisting of silicon dioxide, silicon nitride, spin-on-glass, silicon fluoride and polyimide.

23. A capacitor, comprising:

a first conductive plate;

a layer of ferroelectric material on the first conductive plate;

a second conductive plate on the layer of ferroelectric material;

a diffusion barrier material over the second conductive plate and a part of the ferroelectric material, wherein the diffusion barrier material has residual internal tensile stress in its structure; and

an insulative material over the diffusion barrier material, wherein the insulative material has residual internal compressive stress in its structure.

24. The capacitor of claim 23 wherein:

the residual tensile stress in the diffusion barrier material and the residual compressive stress in the insulative material cancel one another.

25. An integrated circuit device comprising:

a substrate;

a first capacitor plate formed on the substrate;

a layer of ferroelectric material formed on the first capacitor plate;

a second capacitor plate formed over part of the ferroelectric material;

an oxygen diffusion barrier layer material deposited over the second capacitor plate and an exposed part of the ferroelectric material; and

a layer of insulative material deposited over the diffusion barrier layer;

wherein the oxygen diffusion barrier layer material is graded and/or comprises a material selected from the group consisting of tantalum oxide and niobium oxide.

26. An integrated circuit device comprising:

a substrate;

a first capacitor plate formed on the substrate;

a layer of ferroelectric material formed on the first capacitor plate;

a second capacitor plate formed over part of the ferroelectric material; and

a layered dielectric stack comprising diffusion barrier material layers and insulative material layers in alternating sequence with one another, including at least two diffusion barrier layers and at least two insulative material layers, deposited over the second capacitor plate and an exposed part of the ferroelectric material.

27. An integrated circuit device comprising:

a substrate;

a first capacitor plate formed on the substrate;

a layer of ferroelectric material formed on the first capacitor plate;

a second capacitor plate formed over part of the ferroelectric material;

an oxygen diffusion barrier layer material, comprising a material selected from the group consisting of tantalum oxide and niobium oxide, deposited over the second capacitor plate and an exposed part of the ferroelectric material; and

a layer of insulative material deposited over the diffusion barrier layer.

28. An integrated circuit device comprising a ferroelectric capacitor on a substrate, wherein the capacitor is isolated from material detrimental to electrical characteristics of the capacitor, by an oxygen diffusion barrier layer material selected from tantalum oxide, niobium oxide, and graded materials deposited over the capacitor and directly on the substrate surrounding the capacitor.