International Business Machines Corporation
Hybrid gate stack integration for stacked vertical transport field-effect transistors

Abstract:

A method of forming a semiconductor structure includes forming one or more vertical fins each including a first semiconductor layer providing a vertical transport channel for a lower vertical transport field-effect transistor (VTFET) of a stacked VTFET structure, an isolation layer over the first semiconductor layer, and a second semiconductor layer over the isolation layer providing a vertical transport channel for an upper VTFET of the stacked VTFET structure. The method also includes forming a first gate stack including a first gate dielectric layer and a first gate conductor layer surrounding a portion of the first semiconductor layer of the vertical fins. The method further includes forming a second gate stack including a second gate dielectric layer and a second gate conductor layer surrounding a portion of the second semiconductor layer of the vertical fins. The first gate conductor layer and the second gate conductor layer are the same material.