Structure Effects on Resistive Switching of $ \hbox{Al/TiO}_{x}/\hbox{Al}$ Devices for RRAM Applications

Resistive switching characteristics are investigated for $ \hbox{Al/TiO}_{x}/\hbox{Al}$ devices, particularly for the structural effects in crossbar and via-hole-type devices. The via-hole structure shows more reliable switching characteristics than the crossbar structure, owing to the elimination of possible edge effects. The asymmetric switching behavior is analyzed with top $\hbox{Al}/\hbox{TiO}_{x}$ and bottom $\hbox{Al}/\hbox{TiO}_{x}$ interfaces. A trap-controlled space-charge-limited-current model is proposed as a possible switching mechanism, and it is verified that switching mainly occurs on the top electrode/$\hbox{TiO}_{x}$ interface side.