Dual storage node memory
View Patent ↗An embodiment of the present invention is directed to a memory cell. The memory cell includes a first charge storage element and a second charge storage element, wherein the first and second charge storage elements include nitrides. The memory cell further includes an insulating layer formed between the first and second charge storage elements. The insulating layer provides insulation between the first and second charge storage elements.
1. A memory cell comprising:
a first charge storage element;
a second charge storage element, wherein the first and second charge storage elements comprise nitrides; and
an insulating layer formed between the first and second charge storage elements, the insulating layer for providing insulation between the first and second charge storage elements wherein the top surface of the insulating layer is formed to lie below the top surfaces of the first and second charge storage elements wherein an oxide layer is formed underneath the recited insulating layer and first and second charge storage elements and the oxide layer and the insulating layer are formed of different materials.
2. The memory cell as recited in claim 1 further comprising:
a substrate; and
silicon oxide pillars formed over the substrate at opposite sides of the memory cell, wherein the first charge storage element, second charge storage element, and insulating layer are formed between the silicon oxide pillars.
3. The memory cell as recited in claim 1 wherein the nitrides are selected from the group consisting of silicon nitride and silicon enriched nitride.
4. The memory cell as recited in claim 1 further comprising:
a first source/drain region;
a second source/drain region formed at an opposite side of the memory cell from the first source/drain region; and
a channel between the first and second source/drain regions, the channel comprising:
a first vertical portion in contact with the first source/drain region;
a horizontal portion in contact with the first vertical portion; and
a second vertical portion in contact with the horizontal portion and the second source/drain region.
5. The memory cell as recited in claim 1 , wherein the nitrides are selected from the group consisting of high-K materials.
6. The memory cell as recited in claim 2 , wherein the silicon oxide pillars are 1000 angstroms thick.
7. The memory cell as recited in claim 1 , wherein the insulating layer comprises silicon oxide.
8. The memory cell as recited in claim 1 , wherein the first and second charge storage elements are each 20-50 nm wide.
9. The memory cell as recited in claim 8 , wherein the first and second charge storage elements and the insulation layer are a combined 100-200 nm wide.
10. The memory cell as recited in claim 1 , further comprising:
a plurality of word lines that are formed of etched conductive material, wherein the conductive material makes contact with oxide pillars located at opposite sides of the etched conductive material and the first and second charge storage elements.
11. The memory cell as recited in claim 10 , wherein the conductive material comprises polysilicon.
12. The memory cell as recited in claim 1 , wherein the first and second charge storage elements each comprise a first oxide layer, a charge storage layer in contact with the first oxide layer, and a second oxide layer in contact with the charge storage layer.
13. The memory cell as recited in claim 12 , wherein the first oxide layer, the charge storage layer, and the second oxide layer are 30-100, 50-120, and 30-100 angstroms thick, respectively.