Characterization of Resistive Switching Behaviors of RF Sputtered Si Oxide Resistive Random Access Memories with Ti-Based Electrodes

We have fabricated metal-insulator-metal (MIM) diodes with a radio frequency (RF) sputtered Si oxide (SiOx) dielectric layer and studied the impact of three kinds of top electrodes (Ti, TiN, and Pt) on the resistive switching characteristics of the MIM diodes by current-voltage (I-V) measurements. For the MIM diodes with Ti-based electrodes, a significant increase in the initial current level and a decrease in the ON/OFF resistance rate were observed as compared to those of the reference MIM diodes with the Pt top electrodes. To gain a better understanding of the changes in the current levels with the top electrodes, the chemical bonding features in the region near the interface between the top electrode and SiOx layer were investigated using hard X-ray photoemission spectroscopy (HAXPES) under synchrotron radiation (hv = 7939 eV). From HAXPES analyses, it was found that the SiOx surface partially reacted with the Ti and TiN top electrodes during the deposition. Due to the formation of a TiOx barrier layer at the interface between the TiN top electrode and SiOx layer, distinct bi-polar type resistive switching with lower operation voltages below 2.0 V has been achieved. (C) 2013 The Japan Society of Applied Physics