Resistance variable memory device and method of fabricating the same

1. A method of fabricating a resistance-variable memory device, the method comprising:

forming a plurality of selection devices on a substrate;

forming a first insulating layer including one recessed region which exposes four adjacent selection devices;

forming a conductive layer on the selection devices and the first insulating layer;

patterning the conductive layer in a first direction to form conductive patterns spaced apart from each other and connecting a pair of adjacent selection devices to each other in the first direction;

forming a resistance-variable material layer on the conductive patterns; and

patterning the resistance-variable-material-layer and the conductive patterns in a second direction to form rows of resistance-variable material extending in the second direction and to form lower electrodes spaced apart from one another, such that each lower electrode corresponds to a separate selection device.

2. The method according to claim 1 , wherein the lower electrodes are disposed in the recessed region and in contact with the upper surfaces of the selection devices, respectively.

3. The method according to claim 2 , wherein the conductive layer fills the recessed region,

patterning the conductive layer comprises exposing a second insulation layer between the plurality of selection devices and leaving portions of the conductive layer at locations corresponding to the upper surfaces of the selection devices, and

the method further comprises forming a third insulation layer between remaining portions of the conductive layer.

4. The method according to claim 2 , wherein the conductive layer is formed on a bottom and sides of the recessed region to conform to a shape of the bottom and sides of the recessed region,

patterning the conductive layer comprises exposing a second insulation layer between the plurality of selection devices and leaving portions of the conductive layer at locations corresponding to the upper surfaces of the selection devices, and

the method further comprises forming a third insulation layer between the remaining portions of the conductive layer.

5. The method according to claim 4 , wherein the lower electrodes have an “L” cross-section shape in corners of the recessed region corresponding to the upper surfaces of the plurality of selection devices.

6. The method according to claim 2 , wherein the recessed region has a polygonal shape having corners corresponding to center portions of upper surfaces of the plurality of selection devices.

7. The method according to claim 6 , wherein the selection devices are arranged on the substrate in a grid pattern including rows and columns, and

the recessed region is formed to have polygonal shapes having corners corresponding to the center portions of the upper surfaces of the plurality of diodes in first and second adjacent columns of selection devices.

8. The method according to claim 7 , wherein the lower electrodes are disposed in the corners of the recessed region, the method further comprising:

forming a second insulation layer to contiguously fill the recess,

wherein the variable-resistance material layer is formed to contact upper surfaces of selection devices in the second column of selection devices and a third column of selection devices adjacent to the second column and different from the first column.

9. The method according to claim 1 , further comprising:

forming the plurality of upper electrodes on the resistance variable material to electrically connect to the resistance-variable material,

wherein the plurality of upper electrodes comprises a plurality of rows on an upper surface of the resistance-variable material layer, each row corresponding to a row of the plurality of selection devices.

10. The method according to claim 9 , further comprising:

forming a plurality of conductive word lines on the substrate and forming the plurality of selection devices on the plurality of conductive word lines,

wherein the plurality of upper electrodes extends perpendicular to the plurality of conductive word lines.

11. The method according to claim 10 , further comprising:

forming a plurality of conductive bit lines on the plurality of upper electrodes, the plurality of conductive bit lines formed in rows on the plurality of upper electrodes to correspond to the rows of the plurality of selection devices.

12. The method according to claim 11 , further comprising:

forming an insulation layer to separate each bit line from each other bit line and each upper conductive electrode from each other upper conductive electrode.

13. The method according to claim 12 , further comprising:

forming a plurality of word line contacts to extend from an upper surface of a respective word line to an upper surface of the resistance-variable memory device.