Air-gap spacers for field-effect transistors

    公开(公告)号:US10923389B2

    公开(公告)日:2021-02-16

    申请号:US16288780

    申请日:2019-02-28

    Abstract: Structures for air-gap spacers in a field-effect transistor and methods for forming air-gap spacers in a field-effect transistor. A gate structure is formed on a top surface of a semiconductor body. A dielectric spacer is formed adjacent to a vertical sidewall of the gate structure. A semiconductor layer is formed on the top surface of the semiconductor body. The semiconductor layer is arranged relative to the vertical sidewall of the gate structure such that a first section of the first dielectric spacer is located in a space between the semiconductor layer and the vertical sidewall of the gate structure. A second section of the dielectric spacer that is located above a top surface of the semiconductor layer is removed. An air-gap spacer is formed in a space from which the second section of the dielectric spacer is removed.

    Gate-all-around field effect transistors with robust inner spacers and methods

    公开(公告)号:US10903317B1

    公开(公告)日:2021-01-26

    申请号:US16534317

    申请日:2019-08-07

    Abstract: A gate-all-around field effect transistor (GAAFET) and method. The GAAFET includes nanosheets, a gate around center portions of the nanosheets, and inner spacers aligned below end portions. The nanosheet end portions are tapered from the source/drain regions to the gate and the inner spacers are tapered from the gate to the source/drain regions. Each inner spacer includes: a first spacer layer, which has a uniform thickness and extends laterally from the gate to an adjacent source/drain region; a second spacer layer, which fills the space between a planar top surface of the first spacer layer and a tapered end portion of the nanosheet above; and, for all but the lowermost inner spacers, a third spacer layer, which is the same material as the second spacer layer and which fills the space between a planar bottom surface of the first spacer layer and a tapered end portion of the nanosheet below.

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