Memory cell profiles
Examples of the present disclosure provide devices and methods for processing a memory cell. A method embodiment includes removing a key-hole shaped column from a material, to define a profile for the memory cell. The method also includes partially filling the key-hole shaped column with a first number of materials. The method further includes filling the remaining portion of the key-hole shaped column with a second number of materials.
1. A method of forming a plurality of memory cells, comprising:
removing a column from a material to define a profile for the plurality of memory cells, wherein the plurality of memory cells have a cross-sectional shape along a particular plane perpendicular to the column including a circular portion and a projecting rectangular portion;
partially filling an outer portion of the column with a first number of materials;
wherein at least a charge storage material of the first number of materials is formed in the circular portion and in the projecting rectangular portion; and
wherein each of the first number of materials is formed to completely surround an inner portion; and
filling a remaining portion of the column with a second number of materials, wherein at least one of the second number of materials is formed only in the circular portion of the column.
2. A three-dimensional memory device comprising:
a plurality of memory cells in a column formed in a first material, wherein the plurality of memory cells have a cross-sectional shape along a particular plane perpendicular to the column including a circular portion and a projecting rectangular portion, wherein:
an outer portion of the column includes a first number of materials formed therein;
wherein at least a charge storage material of the first number of materials is formed in the circular portion and in the projecting rectangular portion; and
wherein each of the first number of materials is formed to completely surround an inner portion; and
the inner portion of the column includes a second number of materials formed therein, wherein at least one of the second number of materials is formed only in the circular portion of the column.
3. A three-dimensional memory device comprising:
a plurality of memory cells in a number of columns formed in a material, wherein the plurality of memory cells have a cross-sectional shape along a particular plane perpendicular to the number of columns including a number of circular portions and a number of projecting rectangular portions wherein:
an outer portion of each of the number of columns includes a first number of materials formed therein;
wherein at least a charge storage material of the first number of materials is formed in the circular portion and in the proiecting rectangular portion; and
wherein each of the first number of materials is formed to completely surround an inner portion;
the inner portion of each of the number of columns includes a second number of materials formed therein, wherein at least one of the second number of materials is formed only in the circular portion of the column;
a first column and a second column of the number columns including the circular portions and the projecting rectangular portions are aligned in a first line;
a third column and a fourth column of the number columns including the circular portions and the projecting portions are aligned in a second line;
the first line is parallel to the second line; and
the third column is positioned at an equal distance from the first and the second columns.
4. The method of claim 1 , wherein removing the-column comprises:
removing the circular portion in a first stage; and
removing the projecting rectangular portion in a second stage.
5. The method of claim 1 , wherein filling the column with the first number of materials comprises:
partially filling the column from the outer portion of the column towards the inner portion of the column.
6. The method of claim 5 , wherein filling the inner portion of the column with the second number of materials comprises:
filling the inner portion of the column including the circular portion and the projecting rectangular portion from the outer portion towards the inner portion.
7. The method of claim 1 , wherein removing the-column comprises: removing the column through a reactive ion etching process.
8. The method of claim 1 , wherein forming the plurality of memory cells in the column comprises: removing the column in a single stage.
9. The method of claim 1 , wherein the shape of the column comprises a plurality of projecting portions.
10. The method of claim 9 , wherein removing a column from a material comprises removing a star shaped column from the material.
11. The method of claim 1 , wherein the shape of the column includes two projecting rectangular portions, wherein the two projecting rectangular portions are at opposite ends of the circular portion.
12. The method of claim 10 , wherein the shape of the column includes four projecting rectangular portions, wherein the four projecting rectangular portions are equally spaced around the circular portion.
13. The method of claim 9 , wherein the material comprises a first conductor material, the first number of materials comprise a first dielectric material, a second dielectric material, and a second conductor material, and the second number of materials comprise a third dielectric material and a third conductor material and wherein the second conductor material is the charge storage material.
14. The method of claim 13 , wherein the first, the second, and the third conductor materials comprise polysilicon, the first and the third dielectric materials comprise silicon oxide, and the second dielectric material comprises silicon oxide and nitride.
15. The device of claim 2 , wherein the inner portion of the column includes the circular portion and the outer portion of the column includes the circular portion and the projecting rectangular portion.
16. The device of claim 2 , wherein the rectangular portion projecting from the circular portion has a width proportional to the widths of the first number of materials.
17. The device of claim 16 , wherein the width of the rectangular portion projecting from the circular portion is equal to approximately two times a sum of the widths of a second material in the first number of materials, a third material in the first number of materials, and a fourth material in the first number of materials.
18. The device of claim 2 , wherein the first number of materials includes a second material, a third material, and a fourth material and the second number of materials includes a fifth material and a sixth material and wherein the first, the fourth, and the sixth materials comprise polysilicon, the second and the fifth materials comprise silicon oxide, and the third material comprises silicon oxide and nitride.
19. The device of claim 3 , wherein the projecting rectangular portions of the number of columns in the first line are oriented away from the second line and the projecting rectangular portions of the number of columns in the second line are oriented away from the first line.
20. The device of claim 3 , wherein the material comprises a first conductor material and wherein the columns include:
an outer portion that comprises a first dielectric material, a second dielectric material, and a second conductor material; and
an inner portion that comprises a third dielectric material and a third conductor material.
21. The device of claim 20 , wherein the first dielectric material is conformal to the first conductor material, the second dielectric material is conformal to the first dielectric material, the second conductor material is conformal to the second dielectric material, the third dielectric material is conformal to the second conductor material, and the third conductor material is conformal to the third dielectric material.
22. The device of claim 20 , wherein the first, the second, and the third conductor materials comprise polysilicon, the first and the third dielectric materials comprise silicon oxide, and the second dielectric material comprises silicon oxide and nitride.
23. The device of claim 3 , wherein a width of each of the projecting rectangular portions of the number of columns is equal to approximately two times a sum of widths of the first insulating material, the second insulating material, and the second conductor material.
24. The device of claim 18 , wherein the fourth material is the charge storage material.