||In this thesis, silicon dioxide (SiO2) doped hafnium oxide (HfO2) is applied to form low-k doped high-k materials, and the multilayer structure is used to enhance the resistive random access memory (RRAM) properties. Hafnium oxide RRAM device has very fast switching speed, so that it is easy to occure overshooting. The experimental results show that doping through this way can improve its retention. The resistive state was kept stable over 104 second at 85℃, and RRAM with multilayer structure could be operated over 80 million times.|
The second part of this work has applied Fast IV systems to analyze the RRAM electric properties. The response time could be shortened up to 10 ns. To track the reset process of RRAM devices a negative triangle wave pulse bias is applied. It is found that the reset voltage decreases with the increased rising time of the applied pulse. To analyze the experimental data, a critical voltage was defined when the rising time is infinity. When the RRAM device is at reset, and if the operation is slow, the energy will be dissipated. Through the Fast IV measurement method can obtain voltage, current then the time, the energy required before RRAM reset can be calculated. The critical energy and energy dissipation rate can be obtained by varying different raising time of the fast I-V measurement. When the set compliance current is enlarged, the critical energy and energy dissipation rate becomes greater, and the dissipation area become greater. By measuring at low temperature, RRAM filament will be thinner, because the oxidation reaction rates become slow.