Effect of UV irradiation on the resistive switching characteristics of low-temperature solution-processed ZrO2 RRAM

Abstract

This paper presents the fabrication of a solution-processed ZrO2 resistive random access memory (RRAM) device with low-temperature UV irradiation and the effect of UV irradiation on the resistive switching (RS) characteristics. The ZrO2 switching layer was deposited by spin-coating zirconium acetylacetonate (Zr(C5H7O2)4) precursor in an ethanol solvent; the maximum process temperature was 150 °C. The RS characteristics of the fabricated device were unstable for up to 2 h UV irradiation, but they improved after 4 h or longer UV irradiation. The 4 h and 8 h UV-irradiated devices show stable RS even after 200 dc switching cycles and long retention over 104 s. The improvement of RS characteristics caused by different UV irradiation times can be attributed to the reduction of the hydroxyl group (M–OH) and the formation of enhanced metal-oxide bonds (M–O) of the ZrO2 thin films, based on field emission scanning electron microscope and x-ray photoelectron spectroscopy analysis. This research suggests a promising approach to fabricate oxide thin films with good RS characteristics at low temperatures which has high potential to be extended to future flexible RRAM devices.