HfO2/Ti Interface Mediated Conductive Filament Formation in RRAM: An Ab Initio Study

We address the role of the Ti/HfO
₂
interface on the conductive filament (CF) formation within the context of oxide-based resistive random access memories (OxRRAMs). We investigate oxygen defects formation and diffusion at the interface through ab initio calculations. The calculated diffusion energy barriers compare well with the available experimental data. Through the interface region charge analysis and the associated energies with O defect formation and migration into Ti, our results support a probable CF growth from the interface region toward the electron injecting electrode, which acts as a cathode. Hence, for a Ti/HfO
₂
-based OxRRAM supported by the calculation results, we present a pertinent CF growth model by considering its earliest stages, which is relevant for device modeling.