Resistive switching properties of samarium oxide resistive random access memories

Abstract

The bipolar switching and electrical conduction properties of the samarium oxide resistive random access memory (RRAM) device were investigated in this study. By the RF magnetron sputtering method (Sm target, RF power 75 W, chamber pressure 20 mTorr, and different oxygen concentrations), samarium oxide thin films were deposited on an indium tin oxide (ITO)/glass substrate to form a SmOX/ITO structure. Using the metal mask and E-beam evaporation, the aluminum upper electrode was then deposited on it to form an Al/SmOX/ITO metal/insulation/ metal (MIM) structure. Additionally, conventional thermal annealing treatments were used to improve grain growth and the properties of the thin films. From the results, greater than 102 on/off ratio and bipolar switching cycling behaviors of two stable states were obtained. As the operating voltage is low, the conduction mechanisms for low- and high-resistance states are dominated by ohmic conduction behavior for both SET and RESET states. However, as a higher operating voltage is applied, parts of conduction mechanisms will change to space charge limit conduction behaviors. The proposed Al/SmOX/ITO RRAM devices also exhibit good memory window and stable bipolar switching properties during 100 cycles whereas the RF power is 75 W and the oxygen concentration is 10 sccm.