Mechanisms of Oxygen Vacancy Aggregation in SiO2 and HfO2
2019
Dielectric oxide films in electronic devices undergo significant structural changes during
device operation under bias. These changes are usually attributed to aggregation of
oxygen vacancies resulting in formation of oxygen depleted regions and conductive
filaments. However, neutral oxygen vacancies have high diffusion barriers in ionic oxides
and their interaction and propensity for aggregation are still poorly understood. In this
paper we briefly review the existing data on static configurations of neutral dimers
and trimers of oxygen vacancies in technologically relevant SiO2 and HfO2 and then
provide new results on the structure and properties of these defects in amorphous SiO2
and HfO2. These results demonstrate weak interaction between neutral O vacancies,
which does not explain their quick aggregation. We propose that trapping of electrons,
injected from an electrode, by the vacancies may result in creation of new neutral
vacancies in the vicinity of pre-existing vacancies. We describe this mechanism in aSiO2 and demonstrate that this process becomes more efficient as the vacancy clusters
grow larger.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
41
References
16
Citations
NaN
KQI