Nanosheet transistor device with bottom isolation
AssigneeInternational Business Machines Corporation
InventorsRuilong Xie, Veeraraghavan S. Basker, Andrew M. Greene, Pietro Montanini
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Abstract
A method of forming a nanosheet transistor device is provided. The method includes forming a segment stack of alternating intermediate sacrificial segments and nanosheet segments on a bottom sacrificial segment, wherein the segment stack is on a mesa and a nanosheet template in on the segment stack. The method further includes removing the bottom sacrificial layer to form a conduit, and forming a fill layer in the conduit and encapsulating at least a portion of the segment stack.
Claims20
A method of forming a nanosheet transistor device, comprising:
- forming a segment stack of alternating intermediate sacrificial segments and nanosheet segments on a bottom sacrificial segment, wherein the segment stack is on a mesa and a nanosheet template is on the segment stack;
- forming a plug on each of a first side and a second side opposite the first side of the mesa and the bottom sacrificial segment, where the plugs are adjacent to opposite sidewalls of the mesa;
- removing the plugs and the bottom sacrificial segment to form a conduit beneath at least a portion of the segment stack that extends from the first side of the segment stack to the second side of the segment stack opposite the first side;
- and
- forming a fill layer in the conduit that wraps around a portion of the sidewalls and top of the segment stack.
A method of forming a nanosheet transistor device, comprising:
- forming a segment stack of alternating intermediate sacrificial segments and nanosheet segments on a bottom sacrificial segment, wherein the segment stack is on a mesa and a nanosheet template is on the segment stack;
- depositing a stack liner on the nanosheet template, exposed portions of the segment stack, and the mesa;
- depositing a spacer layer on the stack liner;
- forming a gauge block on the spacer layer;
- removing a portion of the spacer layer to form a trench between the gauge block and the bottom sacrificial segment and mesa;
- removing an exposed portion of the stack liner and gauge block to widen the trench;
- removing the nanosheet template;
- forming a plug in the widened trench;
- forming a dummy gate across the segment stack;
- removing the plug and bottom sacrificial segment to form a conduit;
- and
- forming a fill layer in the conduit.
A nanosheet transistor device, comprising:
- a fill layer section on a top surface and at least a portion of opposite sidewalls of a mesa, wherein the mesa is on a substrate;
- one or more nanosheet plates above the fill layer section, wherein the fill layer section is beneath at least a portion of the one or more nanosheet plates and extends from a first side of the one or more nanosheet plates to a second side of the one or more nanosheet plates opposite the first side;
- a gate dielectric layer on the fill layer section and each of the one or more nanosheet plates;
- and
- a conductive gate electrode on the gate dielectric layer to form a first gate structure, wherein a portion of the conductive gate electrode is between the fill layer section and an adjacent nanosheet plate of the one or more nanosheet plates.
Dependencies are inferred from the claim text.