Cross-point memory and methods for fabrication of same
A cross-point memory array includes a plurality of variable resistance memory cell pillars. Adjacent memory cell pillars are separated by a partially filled gap that includes a buried void. In addition, adjacent memory cell pillars include storage material elements that are at least partially interposed by the buried void.
1. A memory device, comprising:
a first memory cell pillar disposed between a lower conductive line and an upper conductive line, the first memory cell pillar comprising a first active element;
a second memory cell pillar separated from the first memory cell pillar in a first direction by a gap; and
a seal region disposed in the gap between the first and second memory cell pillars, the seal region comprising a gap-seal dielectric, wherein the seal region is formed above a buried void, wherein a bottom surface of the seal region forms a top surface of the buried void that terminates before extending to contact a bottom surface of the upper conductive line, wherein the buried void is in contact with at least a portion of the first active element, at least a portion of a middle electrode in contact with the first active element, at least a portion of a second active element in contact with the middle electrode, and at least a portion of opposing side walls of each of the first memory cell pillar and the second memory cell pillar, wherein a first portion of the second active element disposed below the bottom surface of the seal region contacts the gap-seal dielectric disposed in the gap and a second portion of the second active element disposed below the bottom surface of the seal region is separated from the first memory cell pillar or the second memory cell pillar by the buried void.
2. The memory device of claim 1 , wherein the seal region extends from above the buried void to contact the bottom surface of the upper conductive line.
3. The memory device of claim 1 , wherein the first memory cell pillar comprises the second active element, and wherein the bottom surface of the seal region is formed at a vertical location between an upper electrode and the second active element.
4. The memory device of claim 1 , wherein the bottom surface of the seal region is formed at a vertical location disposed between an upper surface of the upper conductive line and an upper surface of a lower electrode.
5. The memory device of claim 1 , wherein the buried void extends vertically from the bottom surface of the seal region to an upper surface of the lower conductive line.
6. The memory device of claim 1 , wherein the buried void extends vertically from the bottom surface of the seal region.
7. The memory device of claim 1 , wherein the gap-seal dielectric is formed over at least a portion of the opposing side walls below the seal region.
8. The memory device of claim 1 , wherein the first memory cell pillar comprises the second active element, wherein at least one of the first active element or the second active element is a storage material and the other of the first active element or the second active element is a selector material.
9. A memory device, comprising:
a first memory cell pillar disposed between a lower conductive line and an upper conductive line, the first memory cell pillar comprising a first active element;
a second memory cell pillar separated from the first memory cell pillar in a first direction by a gap that is at least partially filled with a gap-seal dielectric that forms a seal region; and
a buried void formed underneath the seal region and in contact with at least a portion of the first active element, at least a portion of a middle electrode in contact with the first active element, at least a portion of a second active element in contact with the middle electrode, and at least a portion of opposing side walls of each of the first memory cell pillar and the second memory cell pillar, wherein the seal region is at least partially filled with the gap-seal dielectric covering portions of opposing side walls of the first and second memory cell pillars, wherein the portions of the opposing side walls and a first portion of the second active element disposed below a bottom surface of the seal region contact the gap-seal dielectric disposed in the gap and a second portion of the second active element disposed below the bottom surface of the seal region is separated from the first memory cell pillar or the second memory cell pillar by the buried void, wherein the bottom surface of the seal region forms a top surface of the buried void that terminates before extending to contact a bottom surface of the upper conductive line.
10. The memory device of claim 9 , further comprising:
a second gap disposed above the buried void, wherein the second gap is at least partially filled with a material different than the gap-seal dielectric; and
wherein the second gap comprises an isolation region at least partially filled with the material.
11. The memory device of claim 10 , wherein the gap-seal dielectric and the material are different materials.
12. The memory device of claim 9 , further comprising:
a second gap disposed above the buried void, wherein the second gap is at least partially filled with a material different than the gap-seal dielectric; or
wherein the second gap comprises an isolation region that is unfilled.