Resistive random access memory
A resistive random access memory is provided. The resistive random access memory includes a bottom electrode over a substrate, a top electrode, a resistance-switching layer, an oxygen exchange layer, and a sidewall protective layer. The top electrode is disposed over the bottom electrode. The resistance-switching layer is disposed between the bottom electrode and the top electrode. The oxygen exchange layer is disposed between the resistance-switching layer and the top electrode. The sidewall protective layer containing metal or semiconductor is disposed at sidewalls of the resistance-switching layer, and the sidewalls of the resistance-switching layer is doped with the metal or semiconductor from the sidewall protective layer.
1. A resistive random access memory comprising:
a bottom electrode disposed over a substrate;
a top electrode disposed over the bottom electrode;
a resistance-switching layer disposed between the bottom electrode and the top electrode;
an oxygen exchange layer disposed between the resistance-switching layer and the top electrode; and
a sidewall protective layer disposed at sidewalls of the resistance-switching layer, wherein a material of the sidewall protective layer comprises aluminum-rich aluminum oxide or silicon-rich silicon nitride, and the sidewalls of the resistance-switching layer, the oxygen exchange layer and the bottom electrode are doped with aluminum or silicon from the sidewall protective layer.
2. The resistive random access memory according to claim 1 , wherein oxygen concentration is enhanced near the sidewalls of the oxygen exchange layer.
3. The resistive random access memory according to claim 1 , wherein a thickness of the sidewall protective layer is between 5 nm and 20 nm.
4. The resistive random access memory according to claim 1 , further comprising an oxygen-rich layer disposed between the oxygen exchange layer and the top electrode.
5. The resistive random access memory according to claim 4 , wherein a material of the oxygen-rich layer comprises aluminum oxide, aluminum oxynitride, titanium oxynitride or tantalum oxynitride.
6. The resistive random access memory according to claim 1 , wherein the material of the sidewall protective layer comprises aluminum-rich aluminum oxide, and the sidewall protective layer is doped with nitrogen.
7. The resistive random access memory according to claim 1 , wherein a material of the oxygen exchange layer comprises titanium, titanium-rich titanium nitride, tantalum, hafnium, zirconium, platinum, or aluminum.
8. The resistive random access memory according to claim 1 , wherein the sidewalls of the oxygen exchange layer, the resistance-switching layer, and the bottom electrode constitute a substantially continuous surface, and the substantially continuous surface is doped with aluminum or silicon.
9. The resistive random access memory according to claim 8 , wherein an angle between the substantially continuous surface and a bottom surface of the bottom electrode is 60-90 degrees.
10. The resistive random access memory according to claim 1 , wherein the sidewall protective layer is further disposed at sidewalls of the top electrode.
11. The resistive random access memory according to claim 1 , wherein the sidewall protective layer is a multi-layer.
12. The resistive random access memory according to claim 11 , wherein the multi-layer comprises:
a first liner layer disposed on the substantially continuous surface; and
a second liner layer disposed on the first liner layer.
13. The resistive random access memory according to claim 12 , wherein a material of the first liner layer comprises aluminum-rich aluminum oxide.
14. The resistive random access memory according to claim 13 , wherein a material of the second liner layer comprises aluminum nitride, silicon nitride, tantalum nitride, strontium titanate or bismuth titanate.
15. The resistive random access memory according to claim 1 , wherein the oxygen exchange layer has a rounded top.
16. The resistive random access memory according to claim 1 , wherein the oxygen exchange layer has a rounded bottom, and a barrier is further disposed between the resistance-switching layer and the rounded bottom of the oxygen exchange layer.
17. The resistive random access memory according to claim 16 , wherein a material of the barrier comprises silicon dioxide (SiO 2 ), titanium oxide (TiO 2 ), aluminum oxide (Al 2 O 3 ), tantalum oxide (Ta 2 O 5 ), hafnium oxide (HfO 2 ), or zirconium oxide (ZrO 2 ).
18. The resistive random access memory according to claim 1 , further comprising a block layer disposed between the oxygen exchange layer and the resistance-switching layer, wherein a material of the block layer comprises titanium-doped aluminum oxide, aluminum-doped titanium oxide, tantalum-doped titanium oxide, titanium-doped tantalum oxide, aluminum-doped tantalum oxide, tantalum-doped aluminum oxide, aluminum-doped hafnium oxide, hafnium-doped aluminum oxide, titanium-doped hafnium oxide, hafnium-doped titanium oxide, silicon-doped hafnium oxide, or zirconium-doped hafnium oxide.