Increasing Controllable Oxygen Ions to Improve Device Performance Using Supercritical Fluid Technique in ZnO-Based Resistive Random Access Memory

In this study, an advanced supercritical fluid (SCF) technique that is suitable for materials and electronic devices with low temperature (80 °C) and high pressure (4000 psi) is proposed for a ZnO-based resistive random access memory (RRAM). After an SCF treatment, X-ray photoelectron spectroscopy (XPS) analysis confirms that the concentration of oxygen ions increases in the zinc oxide thin film. Moreover, electrical measurements confirm that the treated ZnO-based random access memory exhibits a lower forming voltage, lower set voltage, and higher ratio of high and low resistance states compared with a device without treatment. Next, the carrier transport mechanism is investigated by fitting the current-voltage curves. Finally, physical models are introduced to illustrate the extra oxygen ions that create better memory characteristics in the random access memory device after the SCF treatment. This significant SCF technique increases the content of oxygen ions without altering the original element ratio and maintains a simple device structure. Thus, the technique shows potential for feasible material improvement capable of effective real applications in the near future.