Semiconductor devices and data storage systems including the same
A semiconductor device includes a substrate; gate electrodes spaced apart from each other and stacked in a direction, perpendicular to an upper surface of the substrate; first and second horizontal conductive layers sequentially stacked between the substrate and the gate electrodes; and a channel structure passing through the gate electrodes and extending perpendicularly, and including a channel layer contacting the first horizontal conductive layer, wherein the channel layer has a region having a reduced diameter below a first level in which a lower surface of a lowermost gate electrode is located, among the gate electrodes, and the channel structure further includes a metal silicide region located below the first level and in the channel structure to contact the channel layer.
1 . A semiconductor device comprising:
a substrate;
gate electrodes apart from each other and stacked in a first direction perpendicular to an upper surface of the substrate;
a first horizontal conductive layer on the substrate and below the gate electrodes;
a second horizontal conductive layer on the first horizontal conductive layer and below the gate electrodes; and
a channel structure passing through the gate electrodes and in a channel hole extending in the first direction, the channel structure including a gate dielectric layer on an inner side surface of and a bottom surface of the channel hole, and a channel layer inside the gate dielectric layer, the channel layer filling the channel hole and contacting the first horizontal conductive layer,
wherein the channel layer includes a first region adjacent to the first horizontal conductive layer and having a first diameter, a second region on the first region, adjacent to the second horizontal conductive layer, and having a second diameter, and a third region on the second region, adjacent the gate electrodes, and having a third diameter, wherein the second diameter is less than the first diameter and less than the third diameter,
the channel structure further includes a metal silicide region at least partially located in at least one of the first region or the second region of the channel layer, and
the channel layer has different degrees of crystallization above and below the metal silicide region.
2 . The semiconductor device of claim 1 , wherein the first region of the channel layer has a polycrystalline structure, and the third region of the channel layer has at least one of a single crystal structure or a single crystal-like structure.
3 . The semiconductor device of claim 1 , wherein the channel layer has a fourth diameter at a first height level between an upper surface of the second horizontal conductive layer and a lower surface of the second horizontal conductive layer, that is less than a fifth diameter at a second height level of the upper surface of the second horizontal conductive layer and less than a sixth diameter at a third height level of the lower surface of the second horizontal conductive layer.
4 . The semiconductor device of claim 1 , wherein the metal silicide region has a first length, longer than the second diameter, in at least one direction.
5 . The semiconductor device of claim 4 , wherein the metal silicide region has a second length, smaller than the first length and smaller than the third diameter, in a direction perpendicular to the one direction.
6 . The semiconductor device of claim 1 , wherein
the metal silicide region has a first length in one direction, and a second length, smaller than the first length, in a direction perpendicular to the one direction, and
the second length is about 0.5 nm to about 5 nm.
7 . The semiconductor device of claim 1 , wherein the first region of the channel layer defines an air gap.
8 . The semiconductor device of claim 7 , wherein the metal silicide region contacts the air gap.
9 . The semiconductor device of claim 7 , wherein the third region of the channel layer does not have an air gap and does not have a seam.
10 . The semiconductor device of claim 1 , wherein the gate dielectric layer comprises a blocking layer, a charge storage layer, and a tunneling layer, the blocking layer, the charge storage layer, and the tunneling layer sequentially stacked,
wherein the blocking layer has a first thickness on side surfaces of the gate electrodes, and a second thickness, greater than the first thickness, on a side surface of the second horizontal conductive layer.
11 . The semiconductor device of claim 10 , wherein the metal silicide region is in contact with at least one of the channel layer, the first horizontal conductive layer, or the tunneling layer.
12 . The semiconductor device of claim 1 , wherein the metal silicide region comprises at least one of nickel silicide (NiSi), titanium silicide (TiSi), cobalt silicide (CoSi), or tungsten silicide (WSi).
13 . The semiconductor device of claim 1 , further comprising:
circuit elements below the substrate and electrically connected to the gate electrodes and the channel structure.
14 . The semiconductor device of claim 1 , wherein an upper surface of the metal silicide region and a lower surface of the metal silicide region are in contact with the channel layer.
15 . A semiconductor device comprising:
a substrate;
gate electrodes spaced apart from each other and stacked in a direction perpendicular to an upper surface of the substrate;
first and second horizontal conductive layers sequentially stacked between the substrate and the gate electrodes; and
a channel structure passing through the gate electrodes and extending perpendicularly, and including a channel layer contacting the first horizontal conductive layer,
wherein the channel layer has a region having a reduced diameter below a first level in which a lower surface of a lowermost one of the gate electrodes is located,
the channel structure further includes a metal silicide region below the first level and in the channel structure to contact the channel layer, and
the channel layer comprises a first region on the metal silicide region and a second region disposed below the metal silicide region.
16 . The semiconductor device of claim 15 , wherein the channel structure further comprises a gate dielectric layer on an outer side surface of the channel layer, and a channel buried insulating layer on an inner side surface of the channel layer,
the channel layer comprises a third region above the first level and having a cylindrical shape surrounding the channel buried insulating layer, and a fourth region below the first level and having a pillar shape.
17 . The semiconductor device of claim 15 , wherein the channel layer comprises a third region above the first level and having a polycrystalline structure, and a fourth region disposed below the first level and having at least one of a single crystal structure or a single crystal-like structure.
18 . The semiconductor device of claim 15 , wherein the metal silicide region is between the first level and a second level on which the upper surface of the substrate is located.
19 . A data storage system comprising:
a semiconductor storage device including a substrate, circuit elements on one side of the substrate, and an input/output pad electrically connected to the circuit elements; and
a controller electrically connected to the semiconductor storage device through the input/output pad and configured to control the semiconductor storage device,
wherein the semiconductor storage device further includes,
gate electrodes apart from each other and stacked in a direction, perpendicular to an upper surface of the substrate,
first and second horizontal conductive layers sequentially stacked between the substrate and the gate electrodes, and
a channel structure passing through the gate electrodes and extending perpendicularly, and including a channel layer contacting the first horizontal conductive layer,
wherein the channel layer has a region having a reduced diameter below a first level in which a lower surface of a lowermost gate electrode is located, among the gate electrodes,
the channel structure further includes a metal silicide region below the first level and in the channel structure and contacting the channel layer, and
the channel layer comprises a first region on the metal silicide region and a second region disposed below the metal silicide region.
20 . The data storage system of claim 19 , wherein the channel layer has crystallization degree above the metal silicide region and a different crystallization degree below the metal silicide region.