Enhanced resistive switching performance of aluminum oxide dielectric with a low temperature solution-processed method

Abstract

We reported a low-temperature solution-processed method for the fabrication of AlOx thin films in the memory device. The detailed study is carried out to figure out the effect of varying annealing temperatures (150, 200, 250, 300, and 350 °C) on resistive switching characteristics of solution-processed aluminum oxide dielectric. The dielectric properties of AlOx films under different annealing temperatures were evaluated by atomic force microscopy (AFM), thermogravimetric analysis-differential scanning calorimetry (TGA-DSC), X-ray diffraction (XRD), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) firstly. Then the AlOx films were used as the switching dielectric layer for a variety of low-temperature solution-processed oxide resistive random access memory (RRAM) devices. It was found that forming voltage increased with increasing annealing temperature and forming free behavior could be achieved by 200 °C sample. No repeatable resistance switching characteristics were observed in the devices with minimum (150 °C) and maximum (350 °C) annealing temperatures. Compared with the ALD-derived AlOx based RRAM devices in previous study, enhanced performance like small forming voltage, large resistance ratio (〈1 8 0) and narrow resistance and voltage distribution was achieved by the solution-processed AlOx based ones at the optimized low annealing temperatures of 200 to 250 °C, which would be applied in the bionic circuit simulated by synapses and neural networks. All three samples (200, 250, and 300 °C) obtained switching endurance up to 300 cycles and data retention over 104 s. Furthermore, the solution based fabrication method also has the potential in the flexible memory application due to the merit of the low-temperature process.