Air-gap spacers for field-effect transistors

    公开(公告)号:US10319627B2

    公开(公告)日:2019-06-11

    申请号:US15376831

    申请日:2016-12-13

    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.

    Nanosheet transistor with uniform effective gate length

    公开(公告)号:US10297664B2

    公开(公告)日:2019-05-21

    申请号:US15486351

    申请日:2017-04-13

    Inventor: Ruilong Xie

    Abstract: A method of forming nanosheet and nanowire transistors includes the formation of alternating epitaxial layers of silicon germanium (SiGe) and silicon (Si), where the germanium content within respective layers of the silicon germanium is systemically varied in order to mediate the selective etching of these layers. The germanium content can be controlled such that voids created by removal of the silicon germanium have uniform dimensions, and the backfilling of such voids with gate dielectric and gate conductor layers proximate to silicon nanosheets or nanowires results in devices having a uniform effective gate length.

    Stacked nanosheet field-effect transistor with air gap spacers

    公开(公告)号:US10269983B2

    公开(公告)日:2019-04-23

    申请号:US15590409

    申请日:2017-05-09

    Abstract: Structures for a nanosheet field-effect transistor and methods for forming a structure for a nanosheet field-effect transistor. A fin is formed that includes a first nanosheet channel layer and a second nanosheet channel layer arranged in a vertical stack. A cavity is formed between a portion of the first nanosheet channel layer and a portion of the second nanosheet channel layer. An epitaxially-grown source/drain region is connected with the portion of the first nanosheet channel layer and the portion of the second nanosheet channel layer. A gate structure is formed that includes a section located in a space between the first nanosheet channel layer and the second nanosheet channel layer. The cavity is surrounded by the first nanosheet channel layer, the second nanosheet channel layer, the section of the gate structure, and the source/drain region to define an air gap spacer.

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