Multi-resistive state memory device with conductive oxide electrodes

Abstract

A memory cell including conductive oxide electrodes is disclosed. The memory cell includes a memory element operative to store data as a plurality of resistive states. The memory element includes a layer of a conductive metal oxide (CMO) (e.g., a perovskite) in contact with an electrode that may comprise one or more layers of material. At least one of those layers of material can be a conductive oxide (e.g., a perovskite such as LaSrCoO 3 -LSCoO or LaNiO 3 -LNO) that is in contact with the CMO. The conductive oxide layer can be selected as a seed layer operative to provide a good lattice match with and/or a lower crystallization temperature for the CMO. The conductive oxide layer may also be in contact with a metal layer (e.g., Pt). The memory cell additionally exhibits non-linear IV characteristics, which can be favorable in certain arrays, such as non-volatile two-terminal cross-point memory arrays.

1 . A re-writeable non-volatile memory device, comprising:
 a re-writeable non-volatile two-terminal memory element including at least one layer of a conductive metal oxide (CMO) operative to store data as a plurality of resistive states and having a first lattice structure; and   a first layer of electrically conductive material in contact with the CMO and having a second lattice structure that substantially matches the first lattice structure,   and wherein the first layer of electrically conductive material comprises ruthenium.   
     
     
         2 . The re-writeable non-volatile memory device of  claim 1 , wherein a first portion of the ruthenium is in direct contact with the CMO and the first portion comprises ruthenium oxide. 
     
     
         3 . The re-writeable non-volatile memory device of  claim 1  and further comprising:
 a second layer of electrically conductive material in direct contact with the first layer of electrically conductive material and the second layer of electrically conductive material is not in contact with the CMO. 
 
     
     
         4 . The re-writeable non-volatile memory device of  claim 3 , wherein the second layer of electrically conductive material comprises a metal or a metal alloy. 
     
     
         5 . The re-writeable non-volatile memory device of  claim 4 , wherein the metal comprises platinum. 
     
     
         6 . The re-writeable non-volatile memory device of  claim 1 , wherein the CMO comprises a perovskite. 
     
     
         7 . The re-writeable non-volatile memory device of  claim 1 , wherein the re-writeable non-volatile two-terminal memory element is positioned between a cross-point of a first conductive array line with a second conductive array line,
 the re-writeable non-volatile two-terminal memory element includes a first terminal directly electrically coupled with the first conductive array line and a second terminal directly electrically coupled with the second conductive array line, and   wherein the re-writeable non-volatile two-terminal memory element is directly electrically in series with its respective first and second conductive array lines.   
     
     
         8 . The re-writeable non-volatile memory device of  claim 7 , wherein the first and second conductive array lines are arranged orthogonally to each other. 
     
     
         9 . The re-writeable non-volatile memory device of  claim 8  and further comprising:
 a two-terminal cross-point array including
 a plurality of the first conductive array lines, 
 a plurality of the second conductive array lines, and 
 a plurality of the re-writeable non-volatile two-terminal memory elements, and 
 
 wherein each re-writeable non-volatile two-terminal memory element is positioned between the cross-point of one of the plurality of the first conductive array lines with one of the plurality of the second conductive array lines. 
 
     
     
         10 . The re-writeable non-volatile memory device of  claim 9 , wherein the plurality of first and second conductive array lines are electrically coupled with front-end-of-the-line (FEOL) active circuitry fabricated on a semiconductor substrate, the two-terminal cross-point array is in contact with the semiconductor substrate and is fabricated directly above the semiconductor substrate, and at least a portion of the FEOL active circuitry configured to access at least one of the re-writeable non-volatile two-terminal memory elements for read operations, write operations, or both read and write operations. 
     
     
         11 . The re-writeable non-volatile memory device of  claim 10 , wherein the two-terminal cross-point array comprises a stacked cross-point array including a plurality of memory layers. 
     
     
         12 . A re-writeable non-volatile memory device, comprising:
 a re-writeable non-volatile two-terminal memory element including at least one layer of a conductive metal oxide (CMO) operative to store data as a plurality of resistive states and having a first lattice structure; and   a first layer of electrically conductive material in contact with the CMO and having a second lattice structure that substantially matches the first lattice structure,   and wherein the first layer of electrically conductive material comprises iridium.   
     
     
         13 . The re-writeable non-volatile memory device of  claim 12 , wherein a first portion of the iridium is in direct contact with the CMO and the first portion comprises iridium oxide. 
     
     
         14 . The re-writeable non-volatile memory device of  claim 12  and further comprising:
 a second layer of electrically conductive material in direct contact with the first layer of electrically conductive material and the second layer of electrically conductive material is not in contact with the CMO. 
 
     
     
         15 . The re-writeable non-volatile memory device of  claim 14 , wherein the second layer of electrically conductive material comprises a metal or a metal alloy. 
     
     
         16 . The re-writeable non-volatile memory device of  claim 15 , wherein the metal comprises platinum. 
     
     
         17 . The re-writeable non-volatile memory device of  claim 12 , wherein the CMO comprises a perovskite. 
     
     
         18 . The re-writeable non-volatile memory device of  claim 12 , wherein the re-writeable non-volatile two-terminal memory element is positioned between a cross-point of a first conductive array line with a second conductive array line,
 the re-writeable non-volatile two-terminal memory element includes a first terminal directly electrically coupled with the first conductive array line and a second terminal directly electrically coupled with the second conductive array line, and   wherein the re-writeable non-volatile two-terminal memory element is directly electrically in series with its respective first and second conductive array lines.   
     
     
         19 . The re-writeable non-volatile memory device of  claim 18 , wherein the first and second conductive array lines are arranged orthogonally to each other. 
     
     
         20 . The re-writeable non-volatile memory device of  claim 19  and further comprising:
 a two-terminal cross-point array including
 a plurality of the first conductive array lines, 
 a plurality of the second conductive array lines, and 
 a plurality of the re-writeable non-volatile two-terminal memory elements, and 
 
 wherein each re-writeable non-volatile two-terminal memory element is positioned between the cross-point of one of the plurality of the first conductive array lines with one of the plurality of the second conductive array lines. 
 
     
     
         21 . The re-writeable non-volatile memory device of  claim 20 , wherein the plurality of first and second conductive array lines are electrically coupled with front-end-of-the-line (FEOL) active circuitry fabricated on a semiconductor substrate, the two-terminal cross-point array is in contact with the semiconductor substrate and is fabricated directly above the semiconductor substrate, and at least a portion of the FEOL active circuitry configured to access at least one of the re-writeable non-volatile two-terminal memory elements for read operations, write operations, or both read and write operations. 
     
     
         22 . The re-writeable non-volatile memory device of  claim 21 , wherein the two-terminal cross-point array comprises a stacked cross-point array including a plurality of memory layers. 
     
     
         23 . A re-writeable non-volatile memory device, comprising:
 a re-writeable non-volatile two-terminal memory element including at least one layer of a conductive metal oxide (CMO) operative to store data as a plurality of resistive states and having a first lattice structure; and   a first layer of electrically conductive material in contact with the CMO and having a second lattice structure that substantially matches the first lattice structure,   and wherein the first layer of electrically conductive material comprises titanium nitride.   
     
     
         24 . The re-writeable non-volatile memory device of  claim 23  and further comprising:
 a second layer of electrically conductive material in direct contact with the first layer of electrically conductive material and the second layer of electrically conductive material is not in contact with the CMO. 
 
     
     
         25 . The re-writeable non-volatile memory device of  claim 24 , wherein the second layer of electrically conductive material comprises a metal or a metal alloy. 
     
     
         26 . The re-writeable non-volatile memory device of  claim 25 , wherein the metal comprises platinum.