Semiconductor devices having transistors with vertical channels and method of fabricating the same
First Claim
1. A semiconductor device comprising:
- a cell array region having a plurality of unit cells, each unit cell having a cell occupation area, repeatedly aligned along a first direction and along a second direction, the first and second directions being perpendicular to each other in a horizontal direction along a primary surface of a semiconductor substrate, wherein each unit cell has a uniform first pitch in the first direction and in the second direction;
an active pillar vertically extending from an active region of each unit cell integrally with the semiconductor substrate in a vertical direction that is perpendicular with respect to the primary surface of the semiconductor substrate, wherein widths of at least a portion of the active pillar in the first direction and in the second direction are equal to a first width 1 F as a minimum feature size in the cell array region;
a ring-shaped gate surrounding a sidewall of the active pillar;
a channel region formed to extend along the active pillar in the vertical direction;
a buried bit line formed below the active pillar in the semiconductor substrate; and
a word line extending in the horizontal direction perpendicular to the buried bit line, and electrically connected to the ring-shaped gate, wherein a distance from the active pillar of any one unit cell of the plurality of unit cells to each of the active pillars of nearest neighboring unit cells in the first direction and the second direction is equal to the first width of the active pillar of one unit cell.
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Abstract
In a semiconductor device and a method of fabricating the same, a vertical channel transistor has a cell occupation area of 4 F2. The semiconductor device comprises: a cell array region having a plurality of unit cells, each unit cell having a cell occupation area, repeatedly aligned along a first direction and along a second direction, the first and second directions being perpendicular to each other in a horizontal direction along a primary surface of a semiconductor substrate, wherein each unit cell has a uniform first pitch in the first direction and in the second direction; an active pillar vertically extending from an active region of each unit cell integrally with the semiconductor substrate in a vertical direction that is perpendicular with respect to the primary surface of the semiconductor substrate, wherein widths of at least a portion of the active pillar in the first direction and in the second direction are equal to a first width 1 F as a minimum feature size in the cell array region; a ring-shaped gate surrounding a sidewall of the active pillar; a channel region formed to extend along the active pillar in the vertical direction; a buried bit line formed below the active pillar in the semiconductor substrate; and a word line extending in the horizontal direction perpendicular to the buried bit line, and electrically connected to the ring-shaped gate, wherein a distance from the active pillar of any one unit cell of the plurality of unit cells to each of the active pillars of nearest neighboring unit cells in the first direction and the second direction is equal to the first width of the active pillar of one unit cell.
125 Citations
33 Claims
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1. A semiconductor device comprising:
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a cell array region having a plurality of unit cells, each unit cell having a cell occupation area, repeatedly aligned along a first direction and along a second direction, the first and second directions being perpendicular to each other in a horizontal direction along a primary surface of a semiconductor substrate, wherein each unit cell has a uniform first pitch in the first direction and in the second direction;
an active pillar vertically extending from an active region of each unit cell integrally with the semiconductor substrate in a vertical direction that is perpendicular with respect to the primary surface of the semiconductor substrate, wherein widths of at least a portion of the active pillar in the first direction and in the second direction are equal to a first width 1 F as a minimum feature size in the cell array region;
a ring-shaped gate surrounding a sidewall of the active pillar;
a channel region formed to extend along the active pillar in the vertical direction;
a buried bit line formed below the active pillar in the semiconductor substrate; and
a word line extending in the horizontal direction perpendicular to the buried bit line, and electrically connected to the ring-shaped gate, wherein a distance from the active pillar of any one unit cell of the plurality of unit cells to each of the active pillars of nearest neighboring unit cells in the first direction and the second direction is equal to the first width of the active pillar of one unit cell. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A semiconductor device comprising:
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a cell array region having a plurality of unit cells, each unit cell having a cell occupation area in a semiconductor substrate;
an active pillar extending in a vertical direction with respect to the substrate from an active region of each unit cell in the cell array region, the active pillar having a first width portion and a second width portion, the second width portion having a width that is greater than a width of the first width portion;
a ring-shaped insulation spacer on a sidewall of the second width portion of the active pillar, the ring-shaped insulation spacer having an inner surface and an outer surface;
a gate dielectric layer on a sidewall of the active pillar;
a ring-shaped gate on a portion of the gate dielectric layer formed on the sidewall of the active pillar, the ring-shaped gate having an inner surface contacting the gate dielectric layer and an outer surface;
a channel region formed to extend in the vertical direction of the active pillar;
a first source/drain region formed at a bottom portion of the active pillar;
a second source/drain region formed at a top portion of the active pillar; and
wherein a width of a widest portion of the outer surface of the ring-shaped gate is equal to or less than that of a widest portion of the outer surface of the ring-shaped insulation spacer. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A method of fabricating a semiconductor device comprising:
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forming a plurality of active pillars on a semiconductor substrate to extend in a vertical direction relative to a horizontal primary surface of the semiconductor substrate, the plurality of active pillars formed integrally with the semiconductor substrate;
forming a gate insulating layer covering a surface of the active pillar;
forming a ring-shaped gate surrounding a sidewall of the active pillar on the gate insulating layer in a region of the active pillar;
implanting ions into a region of the semiconductor substrate adjacent to the ring-shaped gate, thereby forming a bottom source/drain region;
covering an outer surface of the ring-shaped gate and the bottom source/drain region with an etch stop layer;
etching the etch stop layer, the bottom source/drain region, and the semiconductor substrate therebelow in a region between two neighboring active pillars of the plurality of active pillars using a photolithography process, thereby defining a buried bit line below the active pillar in the semiconductor substrate; and
forming a word line electrically connected to the ring-shaped gate in a region between two neighboring active pillars of the plurality of active pillars. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method of fabricating a semiconductor device comprising:
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providing a cell array region having a plurality of unit cells, each unit cell having a cell occupation area in a semiconductor substrate;
forming an active pillar extending in a vertical direction with respect to the substrate from an active region of each unit cell in the cell array region, the active pillar having a first width portion and a second width portion, the second width portion having a width that is greater than a width of the first width portion;
forming a gate dielectric layer on a sidewall of the active pillar;
forming a ring-shaped insulation spacer on a sidewall of the second width portion of the active pillar, the ring-shaped insulation spacer having an inner surface and an outer surface;
forming a ring-shaped gate on a portion of the gate dielectric layer formed on the sidewall of the active pillar, the ring-shaped gate having an inner surface contacting the gate dielectric layer and an outer surface;
forming a channel region formed to extend in the vertical direction of the active pillar;
forming a first source/drain region formed at a bottom portion of the active pillar;
forming a second source/drain region formed at a top portion of the active pillar; and
wherein a width of a widest portion of the outer surface of the ring-shaped gate is equal to or less than that of a widest portion of the outer surface of the ring-shaped insulation spacer. - View Dependent Claims (29, 30, 31, 32, 33)
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Specification