Semiconductor device and formation method
AssigneesTaiwan Semiconductor Manufacturing Company, Ltd., National Taiwan University
InventorsHung-Yu Ye, Yu-Shiang Huang, Chien-Te Tu, Chee-Wee Liu
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Abstract
A device comprises source/drain regions over a substrate and spaced apart along a first direction, a first gate structure between the source/drain regions, and a first channel structure surrounded by the first gate structure. The first channel structure comprises alternately stacking first semiconductor layers and second semiconductor layers. When viewed in a cross section taken along a second direction perpendicular to the first direction, central axes of the second semiconductor layers are laterally offset from central axes of the first semiconductor layers.
Claims20
A device comprising:
- source/drain regions over a substrate and spaced apart along a first direction;
- a first gate structure between the source/drain regions;
- and
- a first channel structure surrounded by the first gate structure, the first channel structure comprising alternately stacking first semiconductor layers and second semiconductor layers, wherein when viewed in a cross section taken along a second direction perpendicular to the first direction, central axes of the second semiconductor layers are laterally offset from central axes of the first semiconductor layers, wherein the second semiconductor layers of the first channel structure electrically connect a first one of the source/drain regions to a second one of the source/drain regions.
A device comprising:
- a source region;
- a drain region separated from the source region along a first direction;
- and
- a channel structure interposing the source region and the drain region, the channel structure comprising alternately stacking first semiconductor layers and second semiconductor layers, wherein when viewed in a cross section taken along a second direction perpendicular to the first direction, the first semiconductor layers have opposite first and second side surfaces, the second semiconductor layers have opposite third and fourth side surfaces, the third side surfaces of the second semiconductor layers are aligned with the first side surfaces of the first semiconductor layers, and the fourth side surfaces of the second semiconductor layers are laterally set back from the second side surfaces of the first semiconductor layers, wherein the second semiconductor layers of the channel structure electrically connect the source region to the drain region.
A method comprising:
- forming a fin structure having a stack of alternating first semiconductor layers and second semiconductor layers over a substrate;
- forming a dielectric wall on a first longitudinal side of the fin structure but not on a second longitudinal side of the fin structure;
- recessing a portion of the fin structure after forming the dielectric wall;
- forming an epitaxial source/drain structure on the recessed portion of the fin structure, the epitaxial source/drain structure contacting a side surface of the dielectric wall;
- performing a first etching process that etches the second semiconductor layers at a faster etch rate than etching the first semiconductor layers;
- after performing the first etching process, performing a second etching process to remove the dielectric wall;
- and
- after removing the dielectric wall, forming a gate structure over the first semiconductor layers and the second semiconductor layers.
Dependencies are inferred from the claim text.