Methods of forming memory cells with air gaps and other low dielectric constant materials
Various embodiments include methods of forming memory cells. In one embodiment, a first dielectric material and a second dielectric material are formed on a substrate. A conductive material is formed between the first dielectric material and the second dielectric material. An opening is formed through the first dielectric material, the second dielectric material, and the conductive material. The conductive material is recessed laterally from the opening to form a recessed control gate and to expose portions of the first dielectric material and the second dielectric material. Portions of a third dielectric material are formed over the exposed portions of the first dielectric material and the second dielectric material and a charge storage element is formed between the portions of the third dielectric material and adjacent to the recessed control gate. Portions of the third dielectric material are substantially removed. Additional methods, as well as apparatuses, are disclosed.
1. A method of forming an apparatus, the method comprising:
forming a first dielectric material;
forming a second dielectric material;
forming a conductive material between the first dielectric material and the second dielectric material;
forming an opening through the first dielectric material, the second dielectric material, and the conductive material;
recessing the conductive material laterally from the opening to form a recessed control gate and to expose portions of the first dielectric material and the second dielectric material;
forming portions of a third dielectric material over the exposed portions of the first dielectric material and the second dielectric material;
forming a charge storage element between the portions of the third dielectric material, and adjacent to the recessed control gate; and
substantially removing the portions of the third dielectric material.
2. The method of claim 1 , further comprising forming portions of a fourth dielectric material over the portions of the third dielectric material, wherein:
forming the charge storage element between the portions of the third dielectric material comprises forming the charge storage element between the portions of the third dielectric material and the fourth dielectric material; and
substantially removing the portions of the third dielectric material comprises substantially removing the portions of the third dielectric material and the fourth dielectric material.
3. The method of claim 1 , wherein substantially removing the portions of the third dielectric material comprises forming air gaps between the charge storage element and the exposed portions of the first dielectric material and the second dielectric material.
4. The method of claim 3 , further comprising forming a tunnel dielectric over the air gaps.
5. The method of claim 1 , wherein recessing the conductive material laterally comprises recessing the conductive material radially from the opening.
6. The method of claim 1 , wherein forming the charge storage element comprises forming a toroidal-shaped floating gate.
7. A method of forming an apparatus, the method comprising:
forming a pair of dielectric materials substantially parallel to one another and to a surface of a substrate;
forming a conductive material between the pair of dielectric materials;
forming an opening through the pair of dielectric materials and the conductive material;
recessing the conductive material laterally from the opening to form a recessed control gate; and
forming a floating gate between and spaced apart from the pair of dielectric materials by a low dielectric constant material, the low dielectric constant material having a dielectric constant less than about 3.5.
8. The method of claim 7 , further comprising forming a ratio of a thickness of the conductive material to a thickness of either of a first of the pair of dielectric materials or a second of the pair of dielectric materials to be about 1.5 to 1.
9. The method of claim 7 , further comprising forming a third dielectric material over the floating gate and over the low dielectric constant material.
10. The method of claim 9 , further comprising forming a thickness of the conductive material to a thickness of the third dielectric material to be from about 10-to-1 to about 4-to-1.
11. The method of claim 9 , wherein the third dielectric material comprises a tunnel material.
12. The method of claim 9 , further comprising forming a second conductive material within the opening and over the third dielectric material.
13. The method of claim 7 , wherein the low dielectric constant material has a dielectric constant of about 2.2.
14. The method of claim 7 , further comprising forming each of the pair of dielectric materials from the same material.
15. The method of claim 7 , further comprising forming each of the pair of dielectric materials from different materials.
16. The method of claim 7 , further comprising forming an etch stop material between the substrate and a first of the pair of dielectric materials, the first of the pair of dielectric materials being more proximate to the substrate that a second of the pair of dielectric materials.
17. A method of forming an apparatus, the method comprising:
forming a first dielectric material and a second dielectric material substantially parallel to one another and to a surface of a substrate, the first dielectric material being more proximate to the substrate than the second dielectric material;
forming a conductive material between the first dielectric material and the second dielectric material;
forming an opening through the second dielectric material, the conductive material, and at least partially through the first dielectric material;
recessing the conductive material laterally from the opening to form a recessed control gate; and
forming a charge storage element having a first surface and a second surface, the first surface and the second surface being substantially separated from the first dielectric material and the second dielectric material by a first air gap and a second air gap, respectively.
18. The method of claim 17 , further comprising forming the charge storage element to have a toroidal shape, the toroidal shape having a cross-section that is substantially rectangular.
19. The method of claim 17 , further comprising forming the charge storage element to have a toroidal shape, the toroidal shape having a cross-section that is substantially square.
20. The method of claim 17 , further comprising forming the first surface to be opposing to the second surface.
21. The method of claim 17 , further comprising forming the first surface and the second surface to be substantially parallel to one another.