Semiconductor device and method of fabricating the same
A semiconductor device includes a first conductive layer extending in a first direction, a second conductive layer extending in a second direction and disposed over the first conductive layer, the first and second directions being substantially perpendicular to each other, and a variable resistance layer disposed over the first conductive layer, the variable resistance layer extending in the second direction. An upper portion of the variable resistance layer is disposed between lower portions of two neighboring second conductive layers including the second conductive layer.
1. A semiconductor device, comprising:
a first conductive layer extending in a first direction;
a second conductive layer extending in a second direction and disposed over the first conductive layer, the first and second directions being substantially perpendicular to each other; and
a variable resistance layer disposed over the first conductive layer, the variable resistance layer extending in the second direction,
wherein an upper portion of the variable resistance layer is disposed between lower portions of two neighboring second conductive layers including said second conductive layer.
2. The semiconductor device of claim 1 , wherein a cross-section of each of the first and second conductive layers has a sidewall spacer shape with a removed top portion.
3. The semiconductor device of claim 1 , wherein the second conductive layer includes a first sidewall contacting the variable resistance layer and a second sidewall having a curved portion, the curved portion including a plurality of subsections having different curvatures.
4. The semiconductor device of claim 1 , wherein the variable resistance layer includes a reservoir layer and a tunnel barrier layer that are formed over the first conductive layer.
5. The semiconductor device of claim 1 , wherein the variable resistance layer includes a reservoir layer and a selector layer that are formed over the first conductive layer.
6. The semiconductor device of claim 4 , wherein the tunnel barrier layer is conformally disposed over the reservoir layer and an exposed portion of the first conductive layer.
7. The semiconductor device of claim 5 , wherein the selector layer is disposed over a top surface of the reservoir layer.
8. The semiconductor device of claim 4 , wherein the tunnel barrier layer comprises a metal oxide layer satisfying a stoichiometric ratio, and the reservoir layer comprises an oxygen-deficient metal oxide layer.
9. The semiconductor device of claim 1 , wherein the variable resistance layer disposed over the first conductive layer corresponds to a first variable resistance layer, and the semiconductor device further comprises:
a third conductive layer extending in the first direction and disposed over the second conductive layer; and
a second variable resistance layer disposed over the second conductive layer and disposed between lower portions of two neighboring third conductive layers including said third conductive layer, the second variable resistance layer extending in the first direction.
10. The semiconductor device of claim 9 , wherein the second conductive layer functions as a bit line and the first conductive layer functions as a word line when a first vertically stacked memory cell including the first variable resistance layer is selected, and the second conductive layer functions as a word line and the third conductive layer functions as a bit line when a second vertically stacked memory cell including the second variable resistance layer is selected.
11. The semiconductor device of claim 1 , wherein two memory cells include the first conductive layer, the variable resistance layer, and the two neighboring second conductive layers.