Memory cells having storage elements that share material layers with steering elements and methods of forming the same

1. A memory cell comprising:

a metal-insulator-metal (MIM) stack including:

a first conductive layer;

a reversible resistivity switching (RRS) layer above the first conductive layer; and

a second conductive layer above the RRS layer, wherein the first conductive layer and/or the second conductive layer comprises a first semiconductor material layer; and

a steering element coupled to the MIM stack, wherein the steering element comprises the first semiconductor material layer.

2. The memory cell of claim 1 , wherein the first semiconductor material layer comprises n-type semiconductor material or a p-type semiconductor material.

3. The memory cell of claim 1 , wherein the first semiconductor material layer comprises n-type silicon or p-type silicon.

4. The memory cell of claim 1 , wherein the steering element further comprises an undoped semiconductor material layer and a p-type semiconductor material layer.

5. The memory cell of claim 1 , wherein the steering element further comprises a p-type semiconductor material layer and an n-type semiconductor material layer.

6. The memory cell of claim 1 , further comprising a silicide layer between the RRS layer and the first semiconductor material layer.

7. The memory cell of claim 1 , further comprising a titanium oxide layer between the RRS layer and the first semiconductor layer.

8. The memory cell of claim 1 , wherein the RRS layer comprises one or more of HfO X , ZrO X , NiO X , TiO X , TaO X , NbO X and Al X O Y .

9. The memory cell of claim 1 , wherein one of the first and second conductive layers comprises heavily doped semiconductor, and the other of the first and second conductive layers comprises metal or metal nitride.

10. The memory cell of claim 1 , further comprising a metal/metal-oxide layer stack between the first and second conductive layers.

11. A method of forming a memory cell, the method comprising:

forming a metal-insulator-metal (MIM) stack including:

a first conductive layer;

a reversible resistivity switching (RRS) layer above the first conductive layer; and

a second conductive layer above the RRS layer, wherein the first conductive layer and/or the second conductive layer comprises a first semiconductor material layer; and

forming a steering element coupled to the MIM stack, wherein the steering element comprises the first semiconductor material layer.

12. The method of claim 11 , wherein the first semiconductor material layer comprises n-type semiconductor material or a p-type semiconductor material.

13. The method of claim 11 , wherein the first semiconductor material layer comprises n-type silicon or p-type silicon.

14. The method of claim 11 , wherein the steering element further comprises an undoped semiconductor material layer and a p-type semiconductor material layer.

15. The method of claim 11 , wherein the steering element further comprises a p-type semiconductor material layer and an n-type semiconductor material layer.

16. The method of claim 11 , further comprising forming a silicide layer between the RRS layer and the first semiconductor material layer.

17. The method of claim 11 , further comprising forming a titanium oxide layer between the RRS layer and the first semiconductor layer.

18. The method of claim 11 , wherein the RRS layer comprises one or more of HfO X , ZrO X , NiO X , TiO X , TaO X , NbO X and Al X O Y .

19. The method of claim 11 , wherein one of the first and second conductive layers comprises heavily doped semiconductor, and the other of the first and second conductive layers comprises metal or metal nitride.

20. The method of claim 11 , further comprising forming a metal/metal-oxide layer stack between the first and second conductive layers.