Theoretical Investigation of High-k Gate Stacks in nano- MOSFETs

This talk deals with the first-principles atomic-scale modeling of the HfO2-based high-k gate-insulator layer of the nanoscale metal-oxide-semiconductor field-effect transistors. The theoretical investigations are based on density functional theory and non-equilibrium Green's function formalisms. One drawback of the high-k gate-insulator, comparing to the standard SiO2, is high density of defects, particularly oxygen vacancies, which leads to several problems such as enhancement of the leakage current, threshold voltage instability, and degradation of the gate-oxide. It is shown based on theoretical calculations that the harmful effects of oxygen vacancies can be partially healed by introducing lanthanum atoms into the defected HfO2 crystal. Finally, a theoretical model, which can quiet well explain the experimental measurements, is introduced for the progressive degradation of the high-k gate-insulators.

• #تحصیلات_و_یادگیری
• #الکترونیک
• #ترانزیستور_ماسفت
• #نانو
• #برق_خواجه_نصیر
• #دکتر_ندیمی