Nonvolatile resistive memory element with a passivated switching layer

Abstract

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.

We claim: 
     
         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.