A semiconductor structure comprises a first nanosheet device having at least one first channel layer and a first gate, a second nanosheet device disposed above the first nanosheet device and having at least one second channel layer and a second gate, and an isolation layer disposed between the first nanosheet device and the second nanosheet device to electrically isolate the first nanosheet device and the second nanosheet device.

A method includes forming a multilayer stack, which includes a plurality of semiconductor nanostructures and a plurality of sacrificial layers. The plurality of semiconductor nanostructures and the plurality of sacrificial layers are located alternatingly. The method further includes laterally recessing the plurality of sacrificial layers to form lateral recesses, performing a doping process to dope a first dopant into the lateral recesses, forming inner spacers in the lateral recesses, performing an anneal process to diffuse the first dopant into the inner spacers, and forming a source/drain region contacting the inner spacers, wherein the source/drain region is electrically coupled to the plurality of semiconductor nanostructures.

Various embodiments of the present disclosure provide a method for forming a semiconductor device structure. In one embodiment, the method includes forming a fin over a substrate, wherein the fin comprises first semiconductor layers and second semiconductor layers alternating stacked. The method also includes forming a sacrificial gate structure over the fin, removing portions of the fin not covered by the sacrificial gate structure, replacing the second semiconductor layers with a sacrificial dielectric material, recessing edge portions of the sacrificial dielectric material to form cavities between the first semiconductor layers, forming a dielectric spacer in the cavities by depositing a conformal layer of a dielectric liner layer on exposed surfaces of each cavity, forming source/drain features on opposite sides of the sacrificial gate structure, and replacing the sacrificial gate structure and the sacrificial dielectric material with a gate structure wrapping around the first semiconductor layers.

A semiconductor device structure and methods of forming the same are described. The method includes forming a fin structure over a substrate and depositing one or more spacers on a portion of the fin structure. The one or more spacers are deposited on sidewalls of the fin structure. The method further includes removing a first portion of the one or more spacers to expose the fin structure and recessing the fin structure. A first byproduct layer is formed on a second portion of the one or more spacers. The method further includes passivating the first byproduct layer, softening the first byproduct layer, removing a portion of the first byproduct layer to expose the recessed fin structure, and further recessing the fin structure.