Gate structures in semiconductor devices

Abstract

A semiconductor device with different configurations of gate structures and a method of fabricating the same are disclosed. The method includes forming a fin structure on a substrate, forming a gate opening on the fin structure, forming an interfacial oxide layer on the fin structure, forming a first dielectric layer over the interfacial oxide layer, forming a dipole layer between the interfacial oxide layer and the first dielectric layer, forming a second dielectric layer on the first dielectric layer, forming a work function metal (WFM) layer on the second dielectric layer, and forming a gate metal fill layer on the WFM layer. The dipole layer includes ions of first and second metals that are different from each other. The first and second metals have electronegativity values greater than an electronegativity value of a metal or a semiconductor of the first dielectric layer.