||In this study, we further research the switching mechanism during reset process in one-transistor-one-resistance random access memory (1T1R) devices.|
When conducting RRAM measurement, step voltage has a great influence on I-V characteristics. In this thesis, fast-IV measurement has been applied on a 1T1R RRAM to explore relations between input energy and switching speed by use of applying fixed period triangle pulse with different rising time. Experiments results shows as increasing input energy, the resistance switching speed will increase at the same time. In addition, heat effect to RRAM switching speed was also investigated, which was seldom discussed in previous studies.
Environment factors in both high temperature (350K) and low temperature (77K) are investigated. We find the input energy easily dissipates in 77K temperature, making switching speed become slow. However, the input energy accumulates between conducting filament and electrode at 350K temperature, creating higher switching speed. Thus, the relation between input energy and switching speed has been proved. Moreover, we calculated the conduction filament temperature by the relationship between Ohmic conduction and temperature for verified the actual operating temperature during reset process.
In addition, we proposed a model to explain the relationship between low resistance state, LRS and reset voltage. In relatively low and high resistance, the reset voltage was dominated by the quantity and distance of oxygen ions which were generated while set process. Moreover, an abnormal trend between low resistance state, LRS and reset voltage were observed in relatively middle resistance. We found out the abnormal trend between LRS and reset voltage was dominated by current thermal effect.
Furthermore, the relationship between reset voltage and high resistance state (HRS) was further research. Under relatively high and low reset voltage, the resistance of HRS was dominated by the quantity and distance of controllable oxygen ions. On the other hand, the resistance of HRS was dominated by current thermal effect under relatively middle reset voltage.
Key words: Resistance Random Access Memory, Reset process, 1T1R, current thermal effect