First-principles study of oxygen vacancy defects in orthorhombic Hf_0.5Zr_0.5O₂/SiO₂/Si gate stack

The gate defect of the ferroelectric HfO 2 -based Si field-effect transistor (Si FeFET) plays a dominant role in its reliability issue. first-principles calculations are an effective method for atomic-scale understanding defects. However, study on defects FeFET stacks, i.e., metal/orthorhombic-Hf 0.5 Zr O /SiO x /Si structure, has not been reported so far. key challenge is construction stack models. Here, atomic structure and property orthorhombic-Hf systematically studied by calculations. We use Hf (130) high-index crystal face as orthorhombic layer construct robust without any gap states based electron counting rule. calculated band offsets show that this type-I alignment. Furthermore, formation energies charge transition levels (CTLs) reveal oxygen vacancy more favorable to form compared with other such interstitial Hf/Zr vacancy, their CTLs mainly localized near conduction minimum valence maximum, agreement experimental results. responsible trapping/de-trapping behavior FeFET. This work provides insight into paves way carry out