Reproducible and reliable resistive switching behaviors of AlOX/HfOX bilayer structures with Al electrode by atomic layer deposition

Abstract

The resistive switching behaviors of AlO_X/HfO_X bilayer structures were investigated. Metal oxides were deposited by atomic layer deposition. Al and Pt were used as top and bottom electrodes, respectively. Compared with AlO_X and HfO_X monolayer structures, the bilayer structure showed lower set/reset voltages and more-uniform resistive switching properties. It also exhibited good data retention and endurance. The Al top electrode may gather oxygen ions from the oxide layer underneath and thereby create oxygen vacancies in the oxide layer. The uniform electrical property of the bilayer structure is attributed to confined formation/rupture of conductive filaments in the HfO_X layer, whereas undissociated filaments in the AlO_X layer nucleate rapid regeneration of filaments.