Trap passivation in memory cell with metal oxide switching element
Non-volatile storage elements having a reversible resistivity-switching element and techniques for fabricating the same are disclosed herein. The reversible resistivity-switching element may be formed by depositing an oxygen diffusion resistant material (e.g., heavily doped Si, W, WN) over the top electrode. A trap passivation material (e.g., fluorine, nitrogen, hydrogen, deuterium) may be incorporated into one or more of the bottom electrode, a metal oxide region, or the top electrode of the reversible resistivity-switching element. One embodiment includes a reversible resistivity-switching element having a bi-layer capping layer between the metal oxide and the top electrode. Fabricating the device may include depositing (un-reacted) titanium and depositing titanium oxide in situ without air break. One embodiment includes incorporating titanium into the metal oxide of the reversible resistivity-switching element. The titanium might be implanted into the metal oxide while depositing the metal oxide, or after deposition of the metal oxide.
1. A method for fabricating a resistive random access memory (RRAM) element, the method comprising:
forming a resistive random access memory (RRAM) element having a bottom electrode that includes a first electrically conductive material, a metal oxide region adjacent to the first electrically conductive material, and a top electrode that includes a second electrically conductive material adjacent to the metal oxide region, forming the resistive random access memory (RRAM) element includes adding a trap passivation material to one or both of the first electrically conductive material, or the second electrically conductive material, the trap passivation material includes one or more of fluorine, hydrogen or deuterium, the trap passivation material passivates traps at one or both of a first interface between the metal oxide region and the bottom electrode or a second interface between the metal oxide region and the top electrode.
2. The method for fabricating a resistive random access memory (RRAM) element of claim 1 , wherein the adding the trap passivation material to one or both of the first electrically conductive material, or the second electrically conductive material includes either:
i) adding the trap passivation material to the first electrically conductive material in situ while depositing the first electrically conductive material; or
ii) depositing the first electrically conductive material and then implanting the trap passivation material into the first electrically conductive material.
3. The method for fabricating a resistive random access memory (RRAM) element of claim 1 , further comprising adding the trap passivation material to the metal oxide region, including:
i) depositing material for the metal oxide region while adding the trap passivation material to the metal oxide region; or
ii) depositing material for the metal oxide region and then implanting the trap passivation material into the metal oxide region.
4. The method for fabricating a resistive random access memory (RRAM) element of claim 1 , wherein the adding the trap passivation material to one or both of the first electrically conductive material, or the second electrically conductive material includes either:
i) adding the trap passivation material to the second electrically conductive material in situ while depositing the second electrically conductive material; or
ii) depositing the second electrically conductive material and then implanting the trap passivation material into the second electrically conductive material.
5. The method for fabricating a resistive random access memory (RRAM) element of claim 1 , wherein the first electrically conductive material includes one or more of doped silicon or SiGe.
6. The method for fabricating a resistive random access memory (RRAM) element of claim 1 , wherein the metal oxide region includes hafnium oxide.
7. The method of claim 1 , wherein forming the resistive random access memory (RRAM) element includes:
forming the RRAM element in a monolithic three dimensional array that includes multiple memory levels formed above a substrate.
8. A resistive random access memory (RRAM) element comprising:
a bottom electrode that includes a first electrically conductive material;
a metal oxide region adjacent to the first electrically conductive material; and
a top electrode adjacent to the metal oxide region and that includes a second electrically conductive material, one or both of the first electrically conductive material or the second electrically conductive material includes a passivation material that passivates traps at least one of a first interface between the metal oxide region and the bottom electrode or a second interface between the metal oxide region and the top electrode, the passivation material includes one or more of fluorine, hydrogen or deuterium.
9. The resistive random access memory (RRAM) element of claim 8 , wherein the metal oxide region includes hafnium oxide.
10. The resistive random access memory (RRAM) element of claim 8 , wherein the first electrically conductive material includes one or more of doped silicon or SiGe.
11. The resistive random access memory (RRAM) element of claim 8 , wherein the first electrically conductive material includes the passivation material, the passivation material passivates traps at the first interface between the metal oxide region and the bottom electrode.
12. The resistive random access memory (RRAM) element of claim 8 , wherein the second electrically conductive material includes the passivation material, the passivation material passivates traps at the second interface between the metal oxide region and the top electrode.
13. The resistive random access memory (RRAM) element of claim 8 , wherein the metal oxide region also includes the passivation material.
14. The resistive random access memory (RRAM) element of claim 8 , wherein the passivation material includes fluorine.
15. A method for fabricating a memory cell, comprising:
forming a steering element; and
forming a reversible resistivity-switching element in series with the steering element, the forming a reversible resistivity-switching element including:
forming a bottom electrode that includes a first electrically conductive material;
forming a metal oxide region adjacent to the first electrically conductive material;
forming a top electrode that includes a second electrically conductive material adjacent to the metal oxide region; and
adding a trap passivation material to the first electrically conductive material, or the second electrically conductive material, the trap passivation material includes one or more of fluorine, hydrogen or deuterium.
16. The method for fabricating a memory cell of claim 15 , wherein the adding a trap passivation material to the first electrically conductive material or the second electrically conductive material includes:
adding the passivation material to the bottom electrode.
17. The method for fabricating a memory cell of claim 15 , further including:
adding the trap passivation material to the metal oxide region.
18. The method for fabricating a memory cell of claim 15 , wherein the adding a trap passivation material to the first electrically conductive material, or the second electrically conductive material includes:
adding the passivation material to the top electrode.
19. The method for fabricating a memory cell of claim 15 , wherein the first electrically conductive material includes one or more of doped silicon or SiGe, the metal oxide region includes hafnium oxide.
20. A monolithic three dimensional array comprising:
a substrate; and
multiple memory levels formed above the substrate, each of the memory levels including a plurality of memory cells, wherein ones of the memory cells comprise:
a bottom electrode that includes a first electrically conductive material;
a metal oxide region adjacent to the first electrically conductive material; and
a top electrode adjacent to the metal oxide region and that includes a second electrically conductive material, one or both of the first electrically conductive material or the second electrically conductive material includes a passivation material that passivates traps at one or both of a first interface between the metal oxide region and the bottom electrode or a second interface between the metal oxide region and the top electrode, the passivation material includes one or more of fluorine, hydrogen or deuterium.