Method and apparatus for a thin film dielectric stack
A system that incorporates teachings of the subject disclosure may include, for example, a thin film capacitor having a substrate, a first electrode layer on the substrate, a first dielectric layer on the first electrode layer where the first dielectric layer has a columnar-oriented grain structure, a group of second dielectric layers stacked on the first dielectric layer where each of the group of second dielectric layers has a randomly-oriented grain structure, and a second electrode layer on the group of second dielectric layers. Other embodiments are disclosed.
1. A thin film capacitor comprising:
a substrate;
a first electrode layer on the substrate;
a first dielectric layer on the first electrode layer, wherein the first dielectric layer has a columnar-oriented grain structure;
a group of second dielectric layers stacked on the first dielectric layer, wherein the group of second dielectric layers is stacked directly on each other, wherein each of the group of second dielectric layers has a randomly-oriented grain structure, wherein at least one of the group of second dielectric layers is formed from a different material from at least one other of the group of second dielectric layers, and wherein an average grain size for the first dielectric layer is different than an average grain size for each of the group of second dielectric layers; and
a second electrode layer on the group of second dielectric layers,
wherein the average grain size for the first dielectric layer is smaller than the average grain size for each of the group of second dielectric layers.
2. The thin film capacitor of claim 1 , wherein the first dielectric layer and at least one of the group of second dielectric layers are each a high density dielectric layer that comprises barium strontium titanate.
3. The thin film capacitor of claim 1 , wherein the first dielectric layer is formed from a different material from at least one of the group of second dielectric layers.
4. The thin film capacitor of claim 1 , wherein the first dielectric layer is between 50 to 500 Angstroms thick, and wherein the group of second dielectric layers has a total thickness between 500 to 50,000 Angstroms, wherein the first electrode layer, the first dielectric layer, the group of second dielectric layers, and the second electrode layer are part of a first capacitor of a multi-stack capacitor that includes a second capacitor having another first dielectric layer, another group of second dielectric layers, and another second electrode layer.
5. The thin film capacitor of claim 4 , wherein the multi-stack capacitor has a mesa structure.
6. The thin film capacitor of claim 1 , further comprising a planarizing and insulating layer over the group of second dielectric layers.
7. The thin film capacitor of claim 6 , further comprising vias etched through the planarizing and insulating layer.
8. A thin film capacitor comprising:
a substrate;
a first electrode layer on the substrate;
a first dielectric layer on the first electrode layer, wherein the first dielectric layer has a columnar-oriented grain structure;
a group of second dielectric layers stacked on the first dielectric layer, wherein the group of second dielectric layers is stacked directly on each other, wherein each of the group of second dielectric layers has a randomly-oriented grain structure, and wherein the first dielectric layer and at least one of the group of second dielectric layers comprises barium strontium titanate; and
a second electrode layer on the group of second dielectric layers,
wherein an average grain size for the first dielectric layer is smaller than an average grain size for each of the group of second dielectric layers.
9. The thin film capacitor of claim 8 , wherein the first dielectric layer is between 50 to 500 Angstroms thick, and wherein the group of second dielectric layers has a total thickness between 500 to 50,000 Angstroms, wherein the first electrode layer, the first dielectric layer, the group of second dielectric layers, and the second electrode layer are part of a first capacitor of a multi-stack capacitor that includes a second capacitor having another first dielectric layer, another group of second dielectric layers, and another second electrode layer.
10. A thin film capacitor comprising:
a substrate;
a first electrode layer on the substrate;
a first dielectric layer on the first electrode layer, wherein the first dielectric layer has a columnar-oriented grain structure;
a group of second dielectric layers stacked on the first dielectric layer, wherein the group of second dielectric layers is stacked directly on each other, wherein each of the group of second dielectric layers has a randomly-oriented grain structure, wherein an average grain size for the first dielectric layer is smaller than an average grain size for each of the group of second dielectric layers; and
a second electrode layer on the group of second dielectric layers, wherein a thickness of the first dielectric layer is different than a thickness of each of the group of second dielectric layers.
11. The thin film capacitor of claim 10 , wherein the first dielectric layer is between 50 to 500 Angstroms thick.
12. The thin film capacitor of claim 10 , wherein the group of second dielectric layers has a total thickness between 500 to 50,000 Angstroms.
13. The thin film capacitor of claim 10 , wherein the first dielectric layer is formed from a different material from at least one of the group of second dielectric layers.
14. The thin film capacitor of claim 10 , wherein the first electrode layer, the first dielectric layer, the group of second dielectric layers, and the second electrode layer are part of a first capacitor of a multi-stack capacitor that includes a second capacitor having another first dielectric layer, another group of second dielectric layers, and another second electrode layer.
15. The thin film capacitor of claim 14 , wherein the multi-stack capacitor has a mesa structure.
16. The thin film capacitor of claim 10 , further comprising a planarizing and insulating layer over the group of second dielectric layers.
17. The thin film capacitor of claim 16 , further comprising vias etched through the planarizing and insulating layer.
18. The thin film capacitor of claim 10 , wherein the first dielectric layer and at least one of the group of second dielectric layers comprise barium strontium titanate.