Resistive switching characteristics of UV-assisted room-temperature-fabricated top-electrode-free SnOx ReRAM
We investigated the resistive switching characteristics of a top-electrode-free SnOx-based resistive switching random access memory (ReRAM) which was fabricated at room temperature. The resistive switching layer was deposited by assistance of UV irradiation after two instances of spin coating of the Tin(II) acetylacetonate (Sn(AcAc)2) precursor. To minimize the coffee ring effect, the mixture of 2-methoxyethanol and ethanol was used as a solvent of the precursor. The resistive switching characteristics of the top-electrode-free device was measured by direct contact of a tungsten probe tip on the SnOx thin film in reference to the bottom ITO electrode. The device fabricated with 8 h of UV irradiation showed stable resistive switching characteristics even after repeating DC sweep switching cycles 200 times. The retention of the fabricated device was over 104 s. It was found that the Ohmic conduction is dominant in the low resistive state and the space charge limited conduction is dominant in the high resistive state. The resistive switching mechanism of this device was proposed as the tin ion-based filament-type ReRAM. The UV irradiation effects on the SnOx thin film were examined by x-ray photoelectron spectroscopy and the SnOx film thickness depending on the time of UV irradiation was measured by a field emission scanning electron microscope.