NONVOLATILE RESISTIVE MEMORY ELEMENT WITH A PASSIVATED SWITCHING LAYER
A nonvolatile resistive memory element has a novel variable resistance layer that is passivated with non-metallic dopant atoms, such as nitrogen, either during or after deposition of the switching layer. The presence of the non-metallic dopant atoms in the variable resistance layer enables the switching layer to operate with reduced switching current while maintaining improved data retention properties.
1 . A method of forming a nonvolatile memory element, the method comprising:
forming a variable resistance layer between first and second electrode layers, wherein the variable resistance layer comprises a metal oxide; and
passivating oxygen vacancies in the metal oxide using non-metallic dopant atoms.
2 . The method of claim 1 , wherein forming the variable resistance layer comprises:
depositing the metal oxide; and
incorporating the non-metallic dopant atoms into the metal oxide.
3 . The method of claim 2 , further comprising depositing the metal oxide concurrently with incorporating the non-metallic dopant atoms into the metal oxide.
4 . The method of claim 2 , wherein depositing comprises using an atomic layer deposition process to deposit the metal oxide.
5 . The method of claim 2 , wherein depositing comprises using a chemical vapor deposition process to deposit the metal oxide.
6 . The method of claim 2 , wherein the non-metallic dopant atoms comprise nitrogen atoms.
7 . The method of claim 6 , wherein incorporating comprises using a decoupled plasma nitridization process to incorporate the non-metallic dopant atoms into the metal oxide.
8 . The method of claim 6 , wherein incorporating comprises using an ion implant process to incorporate the non-metallic dopant atoms into the metal oxide.
9 . The method of claim 2 , wherein incorporating comprises a thermal anneal in an ammonia (NH 3 ) atmosphere.
10 . The method of claim 1 , wherein the non-metallic dopant atoms comprise at least one chemical element selected from the group consisting of nitrogen, chlorine, and fluorine.
11 . The method of claim 1 , wherein the metal oxide comprises at least one chemical element selected from the group consisting of hafnium, zirconium, titanium, tantalum, aluminum, lanthanum, yttrium, dysprosium, and ytterbium.
12 . The method of claim 1 , wherein the variable resistance layer has a thickness between about 10 and 100 angstroms.
13 . A nonvolatile memory element comprising:
a first electrode formed over a substrate;
a variable resistance element formed over the first electrode, wherein the variable resistance element comprises a metal oxide that includes non-metallic dopant atoms disposed in interstitial locations of the metal oxide; and
a second electrode disposed over the variable resistance element.
14 . The nonvolatile memory element of claim 13 , wherein the metal oxide comprises at least one chemical element selected from the group consisting of hafnium, zirconium, titanium, tantalum, aluminum, lanthanum, yttrium, dysprosium, and ytterbium.
15 . The nonvolatile memory element of claim 13 , wherein the non-metallic dopant atoms comprise at least one chemical element selected from the group consisting of nitrogen, chlorine, and fluorine.
16 . The nonvolatile memory element of claim 13 , wherein the variable resistance element comprises up to 3 atomic percent non-metallic dopant atoms.
17 . A nonvolatile memory element comprising:
a first electrode formed over a substrate;
a variable resistance element formed over the first electrode, wherein the variable resistance element comprises a metal oxide that includes dopant atoms that passivate oxygen vacancies in the metal oxide; and
a second electrode disposed over the variable resistance element.
18 . The nonvolatile memory element of claim 17 , wherein the metal oxide comprises at least one chemical element selected from the group consisting of hafnium, zirconium, titanium, tantalum, aluminum, lanthanum, yttrium, dysprosium, and ytterbium.
19 . The nonvolatile memory element of claim 17 , wherein the dopant atoms comprise at least one chemical element selected from the group consisting of nitrogen, chlorine, and fluorine.
20 . The nonvolatile memory element of claim 17 , wherein the variable resistance element comprises up to 3 atomic percent dopant atoms.