ISOLATION LAYERS IN STACKED SEMICONDUCTOR DEVICES

A semiconductor device and methods of fabricating the same are disclosed. The method includes forming a fin structure on a substrate, forming a superlattice structure with first and second nanostructured layers on the fin structure, forming a polysilicon structure around the superlattice structure, forming a source/drain opening within the superlattice structure, forming a first conductivity type S/D region within a first portion of the S/D opening, forming an isolation layer on the first conductivity type S/D region and within a second portion of the S/D opening, forming a second conductivity type S/D region on the isolation layer and within a third portion the S/D opening, and replacing the polysilicon structure and the second nanostructured layers with a gate structure that surrounds the first nanostructured layers. Materials of the first and second nanostructured layers are different from each other and the second conductivity type is different from the first conductivity type.