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.

Fundamental Identification of Defect‐Related Electron Trap in Hf1−xZrxO2 Alloy Gate Dielectric on Silicon: Oxygen Vacancy versus Hydrogen Interstitial

“…That is, the calculated valence band offset between HfO 2 and ZrO 2 is 0.72 eV, which falls in line with the experimental value of 0.69 eV. [35,36] The CBM of the Hf 1Àx Zr x O 2 alloy also decreases with the increase of Zr composition. Such trends could be attributed to the different d orbitals between Hf and Zr atoms.…”

Characterizing the Charge Trapping across Crystalline and Amorphous Si/SiO 2 /HfO 2 Stacks from First-Principle Calculations

“…The strain of the SiO2 part with respect to the Si and HfO2 part is -6.69% and -2%, respectively. These settings are chosen and determined by carefully referencing previous works [21,[32][33][34]. The effect of strain on defect formation energy can be found in several recent works [35,36].…”