Controlling the Current Conduction Asymmetry of HfO2 Metal-Insulator-Metal Diodes by Interposing Al2O3 Layer

Metal-insulator-metal (MIM) diodes with bulk-limited current conduction asymmetry employing interposed Al2O3 layer in 6-nm-thick HfO2 film have been investigated. The current density is decreased as the Al2O3 layer is located far from the electron injection electrode (i.e., cathode). Also, the work function difference of the electrode does not affect the asymmetry of the MIM diodes. Asymmetry of current conduction is attributed to the control of bulk-limited current conduction by the interposed Al2O3 layer. Physicochemical analysis also confirms the dependence of the location of Al2O3 layer on the bulk-limited current asymmetry.