Semiconductor device and method of forming thereof

Abstract

Semiconductor structures and methods of forming the same are provided. An exemplary method includes receiving a workpiece that includes a fin-shaped structure and a dummy gate stack disposed over the fin-shaped structure. The fin-shaped structure includes a fin-shaped base, a bottom semiconductor stack, a middle dielectric layer over the bottom semiconductor stack, and a top semiconductor stack. Each of the top and bottom semiconductor stacks including channel layers interleaved by sacrificial layers. The method further includes recessing a portion of the dummy gate stack to form a trench to expose the fin-shaped structure, removing the sacrificial layers in the top and bottom semiconductor stacks from the trench, removing the channel layers in the top and bottom semiconductor stacks from the trench, and depositing a dielectric feature in the trench. The dielectric feature wraps around the middle dielectric layer.