Variable resistive memory device and method of manufacturing the same
A variable resistive memory device includes a first electrode layer, a variable resistive pattern structure located on the first electrode layer and including a variable resistive layer, a capping layer formed on opposite side walls of the variable resistive pattern structure and including regions having different impurity concentrations, and a second electrode layer formed on the capping layer.
1. A variable resistive memory device, comprising:
a first electrode layer;
a variable resistive pattern structure on the first electrode layer, the variable resistive pattern structure including a variable resistive layer;
a capping layer on opposite side walls of the variable resistive pattern structure, the capping layer including first and second regions having different impurity concentrations, the first region being interposed between the variable resistive pattern structure and the second region; and
a second electrode layer on the capping layer, wherein:
an upper portion of the second region has an impurity concentration that is lower than an impurity concentration of a lower portion of the second region.
2. The variable resistive memory device as claimed in claim 1 , wherein the variable resistive layer is a magnetic tunnel junction (MTJ) layer.
3. The variable resistive memory device as claimed in claim 1 , wherein the variable resistive layer is a phase-change layer or a resistance-change layer.
4. The variable resistive memory device as claimed in claim 1 , wherein the capping layer includes:
a first region contacting the opposite side walls of the variable resistive pattern structure, the first region having a first impurity concentration, and
a second region on the first region, the second region having a second impurity concentration that is lower than the first impurity concentration.
5. The variable resistive memory device as claimed in claim 4 , wherein impurities included in the first region and the second region are hydrogen.
6. The variable resistive memory device as claimed in claim 1 , wherein the capping layer is on a top surface of the variable resistive pattern structure so as to seal the variable resistive pattern structure.
7. The variable resistive memory device as claimed in claim 6 , wherein, in the capping layer:
the first region contacts the top surface and the opposite side walls of the variable resistive pattern structure, the first region having a first impurity concentration, and
the second region is on the first region on the top surface and the opposite side walls of the variable resistive pattern structure, the second region having an impurity concentration that is lower than the first impurity concentration of the first region.
8. The variable resistive memory device as claimed in claim 7 , wherein:
the upper of the second region is disposed over the top surface of the variable resistive pattern structure, and
the lower portion of the second region is disposed over the opposite side walls of the variable resistive pattern structure.
9. A variable resistive memory device, comprising:
a plurality of first signal lines spaced apart from one another and extending in parallel to one another in a first direction;
a plurality of second signal lines arranged above the plurality of first signal lines to be spaced apart from one another and extending in parallel to one another in a second direction that is perpendicular to the first direction; and
a plurality of memory cells arranged at intersections between the plurality of first signal lines and the plurality of second signal lines to be spaced apart from one another, each of the plurality of memory cells including:
a first electrode layer electrically connected to the first signal line or the second signal line;
a variable resistive pattern structure located on the first electrode layer, the variable resistive pattern structure including a variable resistive layer;
a capping layer on opposite side walls of the variable resistive pattern structure, the capping layer including first and second regions having different impurity concentrations, the first region being interposed between the variable resistive pattern structure and the second region; and
a second electrode layer on the capping layer, the second electrode layer electrically connected to the first signal line or the second signal line, wherein:
an upper portion of the second region has an impurity concentration that is lower than an impurity concentration of a lower portion of the second region.
10. The variable resistive memory device as claimed in claim 9 , wherein each memory cell further includes a selection device electrically connected to the first electrode layer or the second electrode layer.
11. The variable resistive memory device as claimed in claim 9 , wherein each of the first signal line and the second signal line is a word line or a bit line.
12. The variable resistive memory device as claimed in claim 9 , wherein the variable resistive pattern structure includes a variable resistive layer including a phase-change layer, and a heating electrode layer is under the phase-change layer.
13. The variable resistive memory device as claimed in claim 9 , wherein the capping layer includes:
a first region contacting the opposite side walls of the variable resistive pattern structure, the first region having a first hydrogen concentration, and
a second region that on the first region, the second region having a second hydrogen concentration that is lower than the first hydrogen concentration of the first region.
14. The variable resistive memory device as claimed in claim 9 , wherein the plurality of memory cells constitute a memory cell array, and a plurality of the memory cell arrays are stacked in a three-dimensional (3D) vertical structure.