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

摘要

We have fabricated metal-insulator-metal (MIM) diodes with a radio frequency (RF) sputtered Si oxide (SiO_x) 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 SiO_x layer were investigated using hard X-ray photoemission spectroscopy (HAXPES) under synchrotron radiation (hv- 7939 eV). From HAXPES analyses, it was found that the SiO_x surface partially reacted with the Ti and TiN top electrodes during the deposition. Due to the formation of a TiO_x barrier layer at the interface between the TiN top electrode and SiO_x layer, distinct bi-polar type resistive switching with lower operation voltages below 2.0 V has been achieved.