International Business Machines Corporation
THRESHOLD VOLTAGE ADJUSTMENT BY INNER SPACER MATERIAL SELECTION

Abstract:

Semiconductor devices and methods of forming the same include forming first recesses in a first stack of alternating sacrificial layers and channel layers. A first inner spacer sub-layer is formed in the first recesses from a first dielectric material. A second inner spacer sub-layer is formed in the first recesses from a second dielectric material, different from the first dielectric material. The sacrificial layers and the first inner spacer sub-layer are replaced with a gate stack in contact with the second inner spacer sub-layer.