Semiconductor structure with gate-all-around devices and stacked finfet devices

Abstract

A method of manufacturing an integrated circuit (IC) includes providing a structure having a fin over a substrate in a region of the IC, a sacrificial gate stack engaging a channel region of the fin, and gate spacers on sidewalls of the sacrificial gate stack. The first layers and the second layers are alternately stacked over the substrate. The method also includes etching the fin adjacent the gate spacers, resulting in source/drain trenches, partially recessing the second layers exposed in the source/drain trenches, resulting in gaps between adjacent layers of the first layers in the fin, depositing inner spacer features in the gaps in the fin, epitaxially growing source/drain features in the source/drain trenches, and replacing the sacrificial gate stack with a metal gate stack. The metal gate stack includes a gate dielectric layer disposed over top and sidewalls of the fin having both the first and the second layers.