US Patent 12062576 Semiconductor devices with a rare earth metal oxide layer

The present disclosure describes a semiconductor device with a rare earth metal oxide layer and a method for forming the same. The method includes forming fin structures on a substrate and forming superlattice structures on the fin structures, where each of the superlattice structures includes a first-type nanostructured layer and a second-type nanostructured layer. The method further includes forming an isolation layer between the superlattice structures, implanting a rare earth metal into a top portion of the isolation layer to form a rare earth metal oxide layer, and forming a polysilicon structure over the superlattice structures. The method further includes etching portions of the superlattice structures adjacent to the polysilicon structure to form a source/drain (S/D) opening and forming an S/D region in the S/D opening.