Fabrication And Characterization Of ZnO Nanowire-based Memristive Device

With the semiconductor technology and industry following Moore's law to obtain rapid development, the electronic information industry, which is supported by the micro-electronics and represented by the computer and the communication technology, has made the human being into the era of m odern information science and technology. However, memory is regard as critical device in information technology, whose integration level and performance are meeting some bottleneck, such as size node, for traditional semiconductor technique gradually reaches to its physical limit. The smaller its size, the more problems. Memristor as the new type of nonvolatile memory has been payed much attention to by both academia and industry, which is of a few advantages, such as simple technique, outstandingly shrunken feature size, and compatibility with traditional CMOS technique, so it is largely competitive in the future memory market.At present, memristors based on film fabrication have been studied more. However, materials based on nanowire have unique physical and chemical performance, whose functional devices will be expected to perform special function or mechanism. The cost of ZnO nanowire raw material is very law. And its preparation method is simple, crystal structure simple symmetry, chemical properties stable. So here memristor will be fabricated based on single ZnO nanowire. ZnO nanowires and other nanostructures are fabricated by chemical vapor deposition method. The copper masks are made by chemical corrosion. The device of Au/ZnO nanowire(NW)/Au memristor is fabricated by lithography processes and one-shadow-mask process in this work respectively. and lithography process used is always influenced by impurities as well. The one-shadow-mask process used to fabricate nanowire memristor can less rely on special facilities, and be operated conveniently, as well as avoid some influence by impurities imported through lithography processes. Its nonpolar resistive switching has been demonstrated in the device by one-shadow-mask process. The bipolar and unipolar switching modes can be activated reversibly unaffected by the scan voltage history when different voltage conditions are applied. The low resistive state(LRS) and high resistive state(HRS) levels are similar for the two operational modes, on-off ratios defined are above 105. While good endurance characteristic are performed, their switching cycles are above 20. Through experiment measure, memristive device based on ZnO nanowire also has recoverable switching functions. Make the investigation of variation in LRS resistances with increasing temperature, which suggests that the LRS device has semiconductor-like behavior. And the possible switching mechanism in the memristor are suggested to base on the discontinuous oxygen vacancy filaments at the surfaces of ZnO NWs. The switching mode versatility in ZnO is expected to broaden the application scope of the device and enable larger flexibility of memristor architecture.