Memory device
According to one embodiment, a memory device includes first to third interconnects, memory cells, and selectors. The first to third interconnects are provided along first to third directions, respectively. The memory cells includes variable resistance layers formed on two side surfaces, facing each other in the first direction, of the third interconnects. The selectors couple the third interconnects with the first interconnects. One of the selectors includes a semiconductor layer provided between associated one of the third interconnects and associated one of the first interconnects, and gates formed on two side surfaces of the semiconductor layer facing each other in the first direction with gate insulating films interposed therebetween.
1. A fabricating method of a memory device comprising:
forming a plurality of global bit lines in a first direction;
forming a semiconductor layer on the global bit lines;
patterning the semiconductor layer in a second direction orthogonal to the first direction;
forming a plurality of gate insulating films on side surfaces of the patterned semiconductor layer;
forming gate electrodes on the side surfaces of the patterned semiconductor layer;
forming a plurality of layers of word lines on the patterned semiconductor layer;
forming a variable resistance material on side surfaces of the word lines; and
forming a plurality of bit lines in contact with the variable resistance material and the upper surface of the semiconductor layer.
2. The method according to claim 1 , wherein the semiconductor layer includes a first semiconductor layer with a first conductivity type, a second semiconductor layer formed on the first semiconductor layer and with a second conductivity type different from the first conductivity type, and a third semiconductor layer formed on the second semiconductor layer and with the first conductivity type, and
a bit line is formed on the third semiconductor layer.
3. The method according to claim 1 , wherein the semiconductor layer includes a first semiconductor layer with a first conductivity type, and a second semiconductor layer formed on the first semiconductor layer and with a second conductivity type different from the first conductivity type,
the method further comprises forming a third semiconductor layer with the first conductivity type,
the third semiconductor layer is in contact with upper surfaces of two second semiconductor layers adjacent in the first direction, and
a bit line is formed on the third semiconductor layer.
4. The method according to claim 1 , wherein the semiconductor layer includes a first semiconductor layer with a first conductivity type, and a second semiconductor layer formed on the first semiconductor layer and with a second conductivity type different from the first conductivity type,
the method further comprises forming a third semiconductor layer with the first conductivity type on an upper surface of the second semiconductor layer,
wherein a part of the upper surface of second semiconductor layer is in contact with the third semiconductor layer, and a remaining part of the upper surface is out of contact with the third semiconductor layer, and
a bit line is formed on the third semiconductor layer.
5. The method according to claim 1 , wherein the word lines extend in a second direction different from the first direction.
6. The method according to claim 1 , wherein the global bit lines and the word lines extend in a direction different from that of the bit lines.
7. The method according to claim 1 , wherein the gate electrode fills in a groove between adjacent patterned semiconductor layers.
8. The method according to claim 1 , wherein the gate electrode does not fill in a groove between adjacent patterned semiconductor layers.
9. The method according to claim 1 , wherein the variable resistance material includes one of HfO, TiO 2 , ZnMn 2 O 4 , NiO, SrZrO 3 , Pr 0.7 Ca 0.3 MnO 3 , and carbon.
10. The method according to claim 1 , wherein the variable resistance material remains in a region between the bit lines adjacent each other, when the bit lines are formed.
11. A fabricating method of a memory device comprising:
successively forming global bit line film and a semiconductor layer;
patterning the global bit line film and the semiconductor layer in a first direction;
filling in grooves generated by the patterning with an insulating film;
patterning the semiconductor layer and the insulating film in a second direction orthogonal to the first direction;
forming a plurality of gate insulating films on side surfaces of the patterned semiconductor layer;
forming gate electrodes on the side surfaces of the patterned semiconductor layer;
forming a plurality of layers of word lines on the patterned semiconductor layer;
forming a variable resistance material on side surfaces of the word lines; and
forming a plurality of bit lines in contact with the variable resistance material and the upper surface of the semiconductor layer.
12. The method according to claim 11 , wherein the semiconductor layer includes a first semiconductor layer with a first conductivity type, a second semiconductor layer formed on the first semiconductor layer and with a second conductivity type different from the first conductivity type, and a third semiconductor layer formed on the second semiconductor layer and with the first conductivity type, and
a bit line is formed on the third semiconductor layer.
13. The method according to claim 11 , wherein the semiconductor layer includes a first semiconductor layer with a first conductivity type, and a second semiconductor layer formed on the first semiconductor layer and with a second conductivity type different from the first conductivity type,
the method further comprises forming a third semiconductor layer with the first conductivity type,
the third semiconductor layer is in contact with upper surfaces of two second semiconductor layers adjacent in the first direction, and
a bit line is formed on the third semiconductor layer.
14. The method according to claim 11 , wherein the semiconductor layer includes a first semiconductor layer with a first conductivity type, and a second semiconductor layer formed on the first semiconductor layer and with a second conductivity type different from the first conductivity type,
the method further comprises forming a third semiconductor layer with the first conductivity type on an upper surface of the second semiconductor layer,
wherein a part of the upper surface of second semiconductor layer is in contact with the third semiconductor layer, and a remaining part of the upper surface is out of contact with the third semiconductor layer, and
a bit line is formed on the third semiconductor layer.
15. The method according to claim 11 , wherein the word lines extend in a second direction different from the first direction.
16. The method according to claim 11 , wherein the global bit line film and the word lines extend in a direction different from that of the bit lines.
17. The method according to claim 11 , wherein the gate electrode fills in a groove between adjacent patterned semiconductor layers.
18. The method according to claim 11 , wherein the gate electrode does not fill in a groove between adjacent patterned semiconductor layers.
19. The method according to claim 11 , wherein the variable resistance material includes one of HfO, TiO 2 , ZnMn 2 O 4 , NiO, SrZrO 3 , Pr 0.7 Ca 0.3 MnO 3 , and carbon.
20. The method according to claim 11 , wherein the variable resistance material remains in a region between the bit lines adjacent each other, when the bit lines are formed.