Carbon doped resistive switching layers
View Patent ↗Provided are carbon doped resistive switching layers, resistive random access memory (ReRAM) cells including these layers, as well as methods of forming thereof. Carbon doping of metal containing materials creates defects in these materials that allow forming and breaking conductive paths as evidenced by resistive switching. Relative to many conventional dopants, carbon has a lower diffusivity in many suitable base materials. As such, these carbon doped materials exhibit structural stability and consistent resistive switching over many operating cycles. Resistive switching layers may include as much as 30 atomic percent of carbon, making the dopant control relatively simple and flexible. Furthermore, carbon doping has acceptor characteristics resulting in a high resistivity and low switching currents, which are very desirable for ReRAM applications. Carbon doped metal containing layer may be formed from metalorganic precursors at temperatures below saturation ranges of atomic layer deposition.
1. A method of forming a resistive random access memory cell, the method comprising:
providing a substrate comprising a first electrode layer into a processing chamber;
flowing a metalorganic precursor into the processing chamber such that a portion of the metalorganic precursor is adsorbed on the substrate; and
flowing an oxidizing agent into the processing chamber such that a portion of the oxidizing agent reacts with the adsorbed metalorganic precursor forming a layer of a metal containing material,
wherein the substrate is maintained at a temperature lower than a saturation range temperature associated with the metalorganic precursor resulting in partial decomposition of the adsorbed metalorganic precursor and in carbon doping of the metal containing material, and
wherein the layer of the carbon doped metal containing material is operable as a resistive switching layer in the resistive random access memory cell;
performing a treatment of the carbon doped metal containing material, the treatment comprising one of plasma treatment or thermal treatment.
2. The method of claim 1 , wherein the treated material has fewer carbon-hydrogen bonds than the untreated material.
3. The method of claim 1 , wherein the treated material has more carbon-carbon and carbon-oxygen bonds than the untreated material.
4. The method of claim 1 , wherein a concentration of carbon in the treated material and the untreated material is substantially the same.
5. The method of claim 1 , wherein the treatment comprises plasma nitridation and incorporates nitrogen into the carbon doped metal containing material.
6. The method of claim 5 , wherein the plasma nitridation is performed for at least 60 seconds and less than 180 seconds.
7. The method of claim 1 , wherein the treatment comprises one of plasma carbonization or thermal carbonization.
8. The method of claim 1 , wherein the metalorganic precursor comprises tetrakis dimethylamido hafnium (TDMAHf), and wherein the substrate is maintained at a temperature of between 300° C. and 340° C. while forming the carbon doped metal containing layer.
9. The method of claim 1 , wherein the metalorganic precursor comprises trimethal aluminum (TMA), and wherein the substrate is maintained at a temperature of 230° C. and 270° C. while forming the carbon doped metal containing layer.
10. The method of claim 1 , wherein the carbon doped metal containing material comprises one of hafnium oxide, aluminum oxide, nickel oxide, or zirconium oxide.
11. The method of claim 1 , wherein a set current of the resistive random access memory cell is less than about 50 microamperes.
12. The method of claim 1 , wherein a reset current of the resistive random access memory cell is less than about 200 microamperes.
13. The method of claim 1 , wherein a thickness of the layer of the carbon doped metal containing material is less than about 100 Angstroms.
14. The method of claim 1 , wherein a thickness of the layer of the carbon doped metal containing material is less than about 50 Angstroms.
15. The method of claim 1 , wherein the first electrode layer comprises doped polysilicon.
16. The method of claim 15 , wherein the layer of the carbon doped metal containing material directly interfaces the first electrode layer.
17. The method of claim 1 , further comprising forming a second electrode layer over the layer of the carbon doped metal containing material, the second electrode layer comprising titanium nitride.
18. A method of forming a resistive random access memory cell, the method comprising:
providing a substrate comprising polysilicon into a processing chamber;
flowing trimethal aluminum (TMA) into the processing chamber such that a portion of TMA is adsorbed on the substrate; and
flowing an oxidizing agent such that a portion of the oxidizing agent reacts with the adsorbed TMA forming a layer of aluminum oxide,
wherein the substrate is maintained at a temperature at a temperature of 230° C. and 270° C. resulting in partial decomposition of TMA and incorporating carbon into the layer of aluminum oxide producing a carbon doped aluminum oxide layer; and
performing a plasma nitridation treatment of the carbon doped aluminum oxide layer,
wherein the treated carbon doped aluminum oxide layer is operable as a resistive switching layer such that the resistive random access memory cell has a set current of less than 50 microamperes and a reset current of the resistive switching layer is less than 200 microamperes.