Techniques for forming vertical transport FET

    公开(公告)号:US10566251B2

    公开(公告)日:2020-02-18

    申请号:US16037993

    申请日:2018-07-17

    Abstract: Techniques for reducing work function metal variability along the channel of VFET devices are provided. In one aspect, a method of forming a VTFET device includes: patterning fins in a wafer; forming bottom source/drains at a base of the fins and bottom spacers on the bottom source/drains; forming gate stacks over the fins including a gate conductor having a combination of work function metals including an outer layer and at least one inner layer of the work function metals; isotropically etching the work function metals which recesses the gate stacks with an outwardly downward sloping profile; isotropically etching the at least one inner layer while covering the outer layer of the work function metals to eliminate the outwardly downward sloping profile of the gate stacks; forming top spacers above the gate stacks; and forming top source and drains at tops of the fins. A VTFET device is also provided.

    Vertical FET with differential top spacer

    公开(公告)号:US10559676B2

    公开(公告)日:2020-02-11

    申请号:US15960078

    申请日:2018-04-23

    Abstract: VTFET devices having a differential top spacer are provided. In one aspect, a method of forming a VTFET device includes: patterning fins in a wafer including NFET and PFET fins; forming bottom source and drains at a base of the NFET/PFET fins; forming bottom spacers on the bottom source and drains; forming gate stacks alongside the NFET/PFET fins that include a same workfunction metal on top of a gate dielectric; annealing the gate stacks which generates oxygen vacancies in the gate dielectric; forming top spacers that include an oxide spacer layer in contact with only the gate stacks alongside the PFET fins, wherein the oxide spacer layer supplies oxygen filling the oxygen vacancies in the gate dielectric only in the gate stacks alongside the PFET fins; and forming top source and drains above the gate stacks at the tops of the NFET/PFET fins. A VTFET device is also provided.

    NANOSHEET SUBSTRATE ISOLATED SOURCE/DRAIN EPITAXY VIA AIRGAP

    公开(公告)号:US20200044023A1

    公开(公告)日:2020-02-06

    申请号:US16050735

    申请日:2018-07-31

    Abstract: Parasitic transistor formation under a semiconductor containing nanosheet device is eliminated by forming an airgap between the source/drain regions of the semiconductor containing nanosheet device and the semiconductor substrate. The airgap is created by forming a sacrificial germanium-containing semiconductor material at the bottom of the source/drain regions prior to the epitaxial growth of the source/drain regions from physically exposed sidewalls of each semiconductor channel material nanosheet of a nanosheet material stack. After inner dielectric spacer formation, the sacrificial germanium-containing semiconductor material can be reflown to seal any possible openings to the semiconductor substrate. The source/drain regions are then epitaxially grown and thereafter, the sacrificial germanium-containing semiconductor material is removed from the structure creating the airgap between the source/drain regions of the semiconductor containing nanosheet device and the semiconductor substrate.

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