Semiconductor device having a vertical channel layer with an impurity region surrounding a dielectric core
A semiconductor device includes a core insulating layer extending in a first direction, an etch stop layer disposed on the core insulating layer, a channel layer extending along a sidewall of the core insulating layer and a sidewall of the etch stop layer, conductive patterns each surrounding the channel layer and stacked to be spaced apart from each other in the first direction, and an impurity region formed in an upper end of the channel layer.
1. A semiconductor device, comprising:
a core insulating layer extending in a first direction;
an etch stop layer disposed on an upper surface of the core insulating layer;
a channel layer surrounding a sidewall of the core insulating layer and a sidewall of the etch stop layer and extending in the first direction;
conductive patterns each surrounding the channel layer and stacked to be spaced apart from each other in the first direction;
an impurity region formed in an upper end of the channel layer; and
a diffusion prevention layer extending between the impurity region and the etch stop layer wherein the diffusion prevention layer forms an interface between the impurity region and the etch stop layer.
2. The semiconductor device of claim 1 , wherein the etch stop layer includes a different material from the channel layer, wherein the material of the channel layer is an undoped semiconductor layer.
3. The semiconductor device of claim 1 , wherein the etch stop layer includes a different material from the channel layer, wherein the material of the channel layer is a doped semiconductor layer including an impurity having a lower concentration than the impurity region.
4. The semiconductor device of claim 1 , wherein the impurity region surrounds the etch stop layer.
5. The semiconductor device of claim 1 , wherein the impurity region surrounds the etch stop layer and a portion of an upper end of the core insulating layer which is adjacent to the etch stop layer.
6. The semiconductor device of claim 1 , wherein the etch stop layer includes at least one of a doped semiconductor layer including an impurity having a lower concentration than the impurity region, an undoped semiconductor layer, a metal layer, a metal-containing layer, and a nitride layer.
7. The semiconductor device of claim 1 , wherein the etch stop layer includes at least one of a doped silicon layer including an impurity having a lower concentration than the impurity region, an undoped silicon layer, a tungsten layer, a titanium nitride layer, an aluminum oxide layer, and a silicon nitride layer.
8. The semiconductor device of claim 1 , wherein the diffusion prevention layer extends along an interface between the etch stop layer and the core insulating layer.
9. The semiconductor device of claim 1 , wherein the diffusion prevention layer includes an oxide layer.
10. The semiconductor device of claim 1 , further comprising:
a contact plug directly contacting the impurity region and the etch stop layer; and
an upper conductive line directly contacting the contact plug.
11. The semiconductor device of claim 1 , further comprising an upper conductive line directly contacting the impurity region and the etch stop layer.
12. The semiconductor device of claim 1 , wherein the conductive patterns include word lines and at least one layer of a select line disposed above the word lines, and wherein the impurity region overlaps the at least one layer of the select line.