Research On Resistive Switching Memory Based On The Binary Metal Oxides

In recent years, with the popularization of the portable equipments such as cellphone, digtal camera, personal PC, planar PC, the non-voltile memory is becoming more and more important. The Flash memory is the mainstream in current semicondtor memory market. However, Flash memory has encountered serious technical challenges to further scaling down. At this background, many new memeories such as ferroelectric random access memory(FeRAM), magnetic random access memory (MRAM), phace change random access memory (PcRAM), and resistive random access memory (RRAM) are suggested as the candidates for the next generation non-voltile memory. Amongst these candidates, RRAM attacts great attention because of the high speed, low power, simple structure, high integratuin density, good scaling down potential. The resistive swithing pehnomeon has been observed in many materials, we focused our attention mainly on the binary transition metal oxide owing to the simple structure, easy fabrication process and compatibility with the complementary metal-oxide semiconductor (CMOS) technology. The HfO2and SiC>2are adopted as active resistive switcing functional material in RRAM device. We fabricated a series of resistive switcing memories, the electrical performances and the resistive switching mechanism are investigated. The thesis contains the following parts:Firstly, we fabricate and systematically investigate the Cu/HfO2:Cu/Pt device. Device shows nonpolar resistive switching characteristic and excellent electrical performances including large storage window (10'in the device with area of3μm×3μm), good endurance (100cycles under DC voltage sweep) and retention (105seconds under room temperature) characteristics. Based on the relationship of the resistiances in both states and testing temperature, we suggest that the resistive switching mechnism is dominated by the formantion and rupture of the Cu conductive filament in the HfO2function materials. By controlling the compliance current in Set process, the multi-level storage can be achieved in the Cu/HfO2:Cu/Pt device.Secondly, the Cu/HfO2/Pt devices are fabricated and the electrical parameters are investigated. Different from the Cu/HfO2:Cu/Pt device, the resistive switching characteristic is bipolar in the Cu/HfO2/Pt device and the yield is lower.Thirdly, the Cu/SiO2:Cu/Pt devices are fabricated and tested. Cu/SiO2:Cu/Pt devices show good electrical characteristic,250cycles can be achieved under the DC voltage sweep, and resistance states are stable in104seconds under room temperature.Thirdly, the Cu/HfO2:Cu/Pt and Cu/SiO2:Cu/Pt devices are tested in the radiation environment in order to verify its potential for space applications. After the bombardment with the dose of3.6×105rad (Si), device show stable electrical performance, indicating radiation hardened characteristic. To investigate the mechanism of the radiation influence, the C-V cuves of the HfO2and SiO2materials are tested. The C-V cuves prove that the trapping charge on oxide is related with the changing elertrical parameters.