Atomic and electronic structures of the native defects responsible for the resistive effect in HfO2: ab initio simulations

• Published in: Microelectronic engineering Vol. 216; p. 111038
• Main Authors: Perevalov, T.V., Islamov, D.R.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15-08-2019; Elsevier BV
• Subjects: Atomic structure; Atoms & subatomic particles; Charge transport; Charge trapping; Clustering; Conductivity; Defects; Density functional theory; Electric fields; First principles; Hafnium oxide; Hole conductivity; Native defects; Oxygen; Oxygen atoms; Oxygen vacancy; RRAM; Vacancies; Hafnium oxide; Density functional theory; RRAM; Native defects; Charge trapping; Oxygen vacancy
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2019.111038

The oxygen vacancy, interstitial oxygen and hafnium, hafnium substituting oxygen and oxygen Frenkel pair in HfO2 are the probable defects which are able to participate in the conducting filament formation in hafnia-based RRAM. In this paper, we studied the atomic and electronic structures of above-listed defects within the first principles simulation. It was found that all studied defects can be involved in the charge transport. Oxygen vacancies are the key defects for the charge transport and RRAM operability. It was suggested that interstitial oxygen atoms make a significant contribution to the HfO2 hole conductivity. The hafnium interstitial competes with an oxygen interstitial and the Frenkel pair in the conducting filament formation in O-poor conditions. The oxygen vacancies and hafnium substituting oxygen pairs atomic structure indicate a tendency to these defects clustering.
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•Vacancies are a key defects in HfO2 transport and conducting filament formation.•Interstitial makes a significant contribution to the HfO2 hole conductivity.•Hf interstitial compete with O interstitial in a filament forming in the O-poor case.•Atomic structure of O vacancies and Hf substituting O pairs exhibit their clustering.