Michael J. Chang, LLC
Techniques for forming vertical transport FET
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.
International Business Machines Corporation
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Choonghyun Kangguo Juntao
Lee Cheng Li