Semiconductor devices including guard ring structures
A semiconductor device includes a substrate partitioned into a cell region, a peripheral circuit region, and an interface region between the cell region and the peripheral circuit region. A guard ring is provided in the interface region of the substrate and surrounds the cell region. A first gate structure is in the cell region, and a second gate structure is in the peripheral circuit region.
1. A semiconductor device comprising:
a substrate including a cell region, a peripheral circuit region, and an interface region between the cell region and the peripheral circuit region;
a guard ring formed in the interface region of the substrate and surrounding the cell region, wherein the guard ring comprises a portion of the substrate at an upper surface of the substrate and is defined by two adjacent isolation layers at the upper surface of the substrate;
a first gate structure in the cell region; and
a second gate structure in the peripheral circuit region.
2. The semiconductor device of claim 1 , wherein an upper surface of the guard ring is formed at the same level as an upper surface of the substrate, and wherein a side wall of the guard ring contacts a side wall of an isolation layer that surrounds the cell region.
3. The semiconductor device of claim 1 , wherein the interface region has a predetermined width, and wherein the guard ring is formed at an entire portion of the interface region.
4. The semiconductor device of claim 1 , wherein the first gate structure comprises:
a first gate insulating layer on an inner wall of a trench in the substrate;
a first gate electrode on the first gate insulating layer, and an upper surface of which is located at a lower level than an upper surface of the substrate; and
a capping layer on the first gate electrode; and
wherein the second gate structure comprises:
a second gate insulating layer on the substrate;
a second gate electrode on the second gate insulating layer; and
a third gate electrode on the second gate electrode.
5. The semiconductor device of claim 4 , further comprising:
a bit line contact electrically connected to an impurity region that is adjacent to the first gate structure; and
a bit line electrically connected to the bit line contact.
6. The semiconductor device of claim 5 , wherein the bit line comprises a substantially same material as a material of the third gate electrode.
7. The semiconductor device of claim 4 , wherein a width of the guard ring is greater than a thickness of the second gate electrode.
8. The semiconductor device of claim 5 , wherein the bit line has a thickness that is substantially the same as a thickness of the third gate electrode.
9. A semiconductor device comprising:
a substrate including a cell region, a peripheral circuit region, and an interface region between the cell region and the peripheral circuit region and surrounding the cell region;
an isolation layer within the substrate in the interface region, wherein a recess is formed in the isolation layer in the interface region;
a plurality of first gate structures in the cell region; and
a second gate structure in the peripheral circuit region.
10. The semiconductor device of claim 9 , wherein the recess is formed in an upper portion of the isolation layer.
11. The semiconductor device of claim 10 , wherein the recess has a predetermined depth from an upper surface of the substrate in a vertical direction.
12. The semiconductor device of claim 10 , wherein a width of the recess is less than or equal to a width of the interface region.
13. The semiconductor device of claim 10 , wherein the second gate structure comprises a gate insulating layer, a first gate electrode, and a second gate electrode that are sequentially formed on the substrate.
14. The semiconductor device of claim 13 , wherein a width of the recess is greater than or equal to a thickness of the first gate electrode.
15. A semiconductor device comprising:
a substrate including a cell region and a peripheral circuit region;
an etch stop structure surrounding the cell region and defining an interface region between the cell region and the peripheral circuit region, wherein the etch stop structure comprises a portion of the substrate defined by two adjacent trench isolation layers surrounding the cell region;
a first gate structure in the cell region; and
a second gate structure in the peripheral circuit region.
16. The semiconductor device of claim 15 , wherein the etch stop structure comprises a recess in the at least one trench isolation layer.
17. The semiconductor device of claim 15 , wherein the etch stop structure comprises a planar portion of the substrate between the at least one trench isolation layer and a second trench isolation layer surrounding the cell region.
18. The semiconductor device of claim 17 , wherein the second gate structure comprises a gate insulating layer on the substrate, a first gate electrode on the second gate insulating layer and a second gate electrode on the first gate electrode;
wherein a width of the etch stop structure is greater than a thickness of the first gate electrode.
19. The semiconductor device of claim 17 , wherein the second gate structure comprises a gate insulating layer on the substrate, a first gate electrode on the second gate insulating layer and a second gate electrode on the first gate electrode;
wherein a width of the etch stop structure is greater than a thickness of the first gate electrode.