Design principles of tuning oxygen vacancy diffusion in SrZrO3 for resistance random access memory

Abstract

Resistance random access memory (RRAM) is known to be a promising candidate for next generation non-volatile memory devices, in which the diffusion of oxygen vacancies plays a key role in resistance switching. Based on first principles calculations and transition state theory, using SrZrO₃ (SZO) as an example, we found that the diffusion energy of an oxygen vacancy strongly depends on its charge states and V²⁺_O contributes mostly to the resistance switching due to its lowest activation energy. To adjust the performance of SZO RRAM, the effects of dopants (Y, V, Nb and Ta) were revealed according to their modifications on the diffusion of V²⁺_O. We found that doping of Y or V has the most significant effect on the performance of RRAM devices. Furthermore, for dopants with various numbers of valence electrons and atomic radius, general design principles were proposed based on their different effects on the RRAM characteristics. Our results will guide the experimentations and pave a new way for the optimization of RRAM devices.