The influence of lanthanum doping on the band alignment in Si/SiO2 /HfO2 gate stack of nano-MOSFETs: A first principles investigation

Abstract

The induced threshold voltage shift due to La doping in HfO2 dielectric layer of n-type metal–oxide–semiconductor field effect transistors (MOSFETs) was studied using first principles calculations. Large supercells with state-of-the-art thicknesses for intermediate oxide (SiO2) and the high-k layer (HfO2) were employed. La2O3 complexes are shown to have the lowest formation energy at the SiO2/HfO2 interface. The induced shift in the band alignment depends on the position of La atoms in the dielectric stack and the desired shift for n-type transistors can be achieved with La doping at the SiO2/HfO2 interface.