Inner spacer formation and contact resistance reduction in nanosheet transistors
AssigneeInternational Business Machines Corporation
InventorsChoonghyun Lee, Kangguo Cheng, JUNTAO LI, Shogo Mochizuki
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Abstract
A nanosheet field effect transistor device includes a semiconductor substrate including a stack of semiconductor nanosheets and a gate structure. The gate structure has an electrically conductive gate contact on the nanosheets and defines a channel region interposed between opposing source or drain (S/D) regions. The nanosheet field effect transistor further includes an electrically conductive cladding layer that encapsulates an outer surface of the S/D regions, and inner spacers on the sidewalls of the gate structure. The inner spacers are interposed between the cladding layer and the gate contact.
Claims20
A method of fabricating a semiconductor device, the method comprising:
- forming a stack of alternating layers of sacrificial nanosheets and semiconductor nanosheets on a semiconductor substrate;
- forming a gate structure on the stack to define a channel region of the semiconductor nanosheets, the channel region interpose between opposing source or drain (S/D) regions;
- depositing a sacrificial layer comprising a first dielectric material on the S/D regions of the semiconductor nanosheets and sidewalls of the sacrificial nanosheets;
- and
- converting a portion of the sacrificial layer into a second dielectric material different form the first dielectric material to form inner spacers of the semiconductor device.
A method of fabricating a semiconductor device, the method comprising:
- forming a stack of alternating layers of sacrificial nanosheets and semiconductor nanosheets on a semiconductor substrate;
- forming a gate structure on the stack to define a channel region of the semiconductor nanosheets, the channel region interpose between opposing source/drain (S/D) regions;
- forming a first cladding layer comprising a first semiconductor material on an outer surface of the S/D regions;
- forming a second cladding layer comprising a second semiconductor material on the first cladding layer to define a S/D contact profile;
- removing the second cladding layer while preserving the first cladding layer to form S/D contact trenches;
- and
- filling the S/D contact trenches with an electrically conductive contact material to form the S/D contacts having the S/D contact profile.
A nanosheet field effect transistor device comprising:
- a semiconductor substrate including a stack of semiconductor nanosheets;
- a gate structure including an electrically conductive gate contact on the nanosheets to define a channel region interposed between opposing source or drain (S/D) regions;
- an electrically conductive cladding layer encapsulating an outer surface of the S/D regions;
- and
- inner spacers on sidewalls of the gate structure, wherein the inner spacers are interposed between the cladding layer and the gate contact.
Dependencies are inferred from the claim text.