Oxygen Vacancy Formation Accompanied by Hf Oligomer in Amorphous-HfOx-Bascd RRAM: A First Principles Study

RRAM is considered as a promising device for future storage and neuromorphic computing applications. The resistive mechanisms can be ascribed to the formation, movement and recombination of oxygen vacancies. In this work, we have studied the oxygen vacancy formation energy in amorphous HfO
_1.8
. It is found that oxygen vacancies potentially relax to Hf oligomers. Oligomers with more Hf-Hfbonds tend to be accompanied by oxygen vacancies with lower formation energies.