Study Of Resistive Switching Characteristics Based On NiO Films

With the rapid development of digital technology, the performance of electronic products is more and more important for people. Memory is one of most critical components of those products. Simultaneously, with the rapid development of semiconductor technology, feature size continue to shrink leading to gate oxide reducing and leakage current increasing, which deteriorates the reliability of flash devices. As a representative of the traditional non-volatile memory, Flash's storage density and operation speed are hardly to improve. The high power consumption of Flash also limits application fields. Therefore, it will be an irresistible trend of new mechanisms non-volatile memory. At present, a variety of new non-volatile memory have been developed. Among these, Resistive Random Access Memory is expected to be next generation memory due to simple construction, high-density mass storage, rapid operation speed, low power consumption and good compatibility with conventional CMOS process.In this paper, NiO ceramic target has been sintering by mono-crystal furnace with Ni2O3 powder and influences of sintering temperature on target have been studied. Then NiO resistance switching devices has been fabricated by both Ni metal target and NiO ceramic target. The influences of different process parameters on the crystal and resistance switching properties of the thin film have been studied by x-ray diffractometer, UV-Vis spectrometer,Ⅰ-Ⅴcurve tracer etc.The results show that:(1) higher sintering temperature benefits crystallization of NiO ceramic target. (2) Sputtering speed is slower with Ni metal target because magnetic field is shielded by Ni. With high sputtering speed, the crystal and defect of ceramic target influent properties of NiO thin film. Considering properties and process complexity, Ni metal target was been using to fabricate NiO resistance switching device. (3) Sputtering time is related to resistance s switching properties. TheⅠ-Ⅴcurve will be linear when sputtering time is to short, because thinner film leading to smaller grain size, higher leakage current. With increasing sputtering time, the stable resistance switching phenomenon has been detected, and Forming voltage and set voltage increasing with sputtering time increasing. (4) Oxide flow influent the mount of Ni holes, which influence the resistance switching properties too. The film shows metallic character when the little oxide flows. With oxide flow increasing, filament formatted Forming process becoming unrefined increasing Reset voltage and current. But too much oxide flow leads to too many Ni holes and low resistance which will terminate the resistance switching properties. (5) The conduction mechanisms dominating the low and high resistive states are Ohmic behavior and Schottky field emission.