Resistive switching characteristics of HfO2 grown by atomic layer deposition

Abstract

Resistive switching characteristics of insulating HfO2 grown by the atomic layer deposition (ALD) technique were investigated. From I-V analyses of a Mo/HfO2/Mo device, the resistive switching behaviors were not symmetric for voltage polarity. These behaviors were well explained on the basis of the different top and bottom HfO2 interface states observed by X-ray photoelectron spectroscopy. For the as-deposited HfO2 film, a low resistance state showed an ohmic conduction behavior but a high resistance state showed a Poole-Frenkel mechanism. Moreover, the operation voltages to switch the resistance states were slightly increased by a 400 degrees C annealing process. The resistive switching behaviors are related to not only the defects in the insulator but also the electrode.