Gate-all-around device with trimmed channel and dipoled dielectric layer and methods of forming the same

Abstract

Semiconductor device and the manufacturing method thereof are disclosed. An exemplary method comprises forming a first stack structure and a second stack structure in a first area over a substrate, wherein each of the stack structures includes semiconductor layers separated and stacked up; depositing a first interfacial layer around each of the semiconductor layers of the stack structures; depositing a gate dielectric layer around the first interfacial layer; forming a dipole oxide layer around the gate dielectric layer; removing the dipole oxide layer around the gate dielectric layer of the second stack structure; performing an annealing process to form a dipole gate dielectric layer for the first stack structure and a non-dipole gate dielectric layer for the second stack structure; and depositing a first gate electrode around the dipole gate dielectric layer of the first stack structure and the non-dipole gate dielectric layer of the second stack structure.