Shallow trench isolation structures and techniques
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChung-Lei Chen, Yen-Liang Lin, Ru-Shang Hsiao
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Abstract
A semiconductor structure is disclosed that includes: a source feature and a drain feature disposed in a substrate; a gate structure disposed above the substrate and between the source feature and the drain feature; and a first ladder shallow trench isolation (STI) feature disposed in the substrate at least partially under the gate structure in a channel region between the source feature and the drain feature, the first ladder STI feature including a plurality of sections of different depths including a first depth section and a second depth section.
Claims20
A semiconductor structure, comprising:
- a source feature and a drain feature disposed in a substrate;
- a gate structure disposed above the substrate and between the source feature and the drain feature;
- and
- a first ladder shallow trench isolation (STI) feature disposed in the substrate at least partially under the gate structure in a channel region between the source feature and the drain feature, the first ladder STI feature comprising a plurality of sections of different depths including a first depth section and a second depth section.
A fabrication method, comprising:
- identifying a first ladder STI feature region in a substrate, wherein the first ladder STI feature region comprises at least a first depth section region and a second depth section region;
- forming a charged implant in the first depth section region;
- removing a first level of substrate material from the first depth section region;
- removing a second level of substrate material from both the first depth section region and the second depth section region thereby forming a ladder STI recess;
- and
- filling the ladder STI recess with STI material thereby forming a ladder STI structure having plurality of sections of different depths including a first depth section and a second depth section.
A semiconductor structure, comprising:
- a source feature comprising a first doped region and a drain feature comprising a second doped region disposed in a substrate;
- a channel region disposed in the substrate between the source feature and the drain feature;
- a gate structure disposed above the channel region, wherein the channel region has a drain side that spans between the second doped region and an area in the substrate that is below a middle position of the gate structure in a lateral direction;
- and
- a first ladder shallow trench isolation (STI) feature disposed on the drain side of the channel region, the first ladder STI feature comprising a plurality of sections of different depths including a first depth section and a second depth section.
Dependencies are inferred from the claim text.