Self-aligned air gap spacer for nanosheet CMOS devices
AssigneeInternational Business Machines Corporation
InventorsShogo Mochizuki, Alexander Reznicek, Joshua M. Rubin, Junli Wang
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Abstract
A semiconductor structure is provided that contains a plurality of vertically stacked and spaced apart semiconductor nanosheets in which an inner spacer liner and an air gap are present. Collectively, each inner spacer liner and air gap combination provides an inner spacer structure that separates a portion of a functional gate structure that surrounds each semiconductor nanosheet from a portion of a source/drain (S/D) semiconductor material structure that is present on each side of the functional gate structure.
Claims9
A method of forming a semiconductor structure, the method comprising:
- providing a fin stack of alternating layers of first semiconductor nanosheets and second semiconductor nanosheets located on a surface of a substrate, wherein a sacrificial gate structure and a gate spacer straddle over a portion of the fin stack;
- recessing each first semiconductor nanosheet to provide a gap between each second semiconductor nanosheet;
- forming an inner spacer liner in a portion of each gap and contacting a remaining portion of one of the first semiconductor nanosheets;
- forming a source/drain (S/D) semiconductor material structure from each vertical end sidewall of each second semiconductor nanosheet, wherein during the forming of the source/drain (S/D) semiconductor material structures an air gap is formed between the inner spacer liner and each source/drain (S/D) semiconductor material structure;
- and
- replacing the sacrificial gate structure and each remaining first semiconductor nanosheet with a functional gate structure.
Dependencies are inferred from the claim text.