|Author's Email Address
||This thesis had been viewed 5357 times. Download 174 times.|
||Materials and Optoelectronic Science|
|Type of Document
||Study on Resistance Switching Characteristics of Hafnium Oxide Thin Film|
|Date of Defense
Concentration of Oxygen
Energy Dissipation Rate
||Resistive Random Access Memory (RRAM) is considered as one of the most promising candidate for the next-generation memories due to their excellent properties such as nonvolatile property, fast operation speed, low operation voltage. Even though RRAM has been extensively studied in recent years, there is still no comprehensive theory to clarify the resistive switching mechanism. Therefore this study mainly focuses on the RRAM switching process to better reveal the characteristics involved in this relative blank area.|
The active layer (hafnium oxide) of RRAM is deposited by Atomic Layer Deposition (ALD) with a thickness of 10nm. Fast IV test technique is applied to track the set process of RRAM devices using positive triangle wave pulse, from which we find that set voltage decreases with the increase of rising time of the applied pulse. By analyzing the experimental data, critical voltage is defined when the rising time is at infinity. Meanwhile we find that the critical voltage is not relevant to temperature but in accordance with the Nernst equation.
Besides RRAM electro-forming process is thoroughly investigated, from which we find the concentration of oxygen rises exponentially with the increase of forming compliance current. And chain reaction model is proposed to clarify this process.
In this study Reset process is also investigated in addition to the Set process. As the structure of the device is Ti/HfO2/TiN, the resistance switch will occur on Ti or TiN electrode. With help of Fast IV measurement, time-voltage-current relationship can be obtained, from which energy needed before reset can be calculated . What’s more we can find the energy dissipation rate of Ti electrode is higher than that of TiN, measured by vary ramp rate voltage pulse. And this results from faster thermal dissipation rate of Ti electrode, which in turn delivers energy to larger amount of oxygen ions with wider range. And this is also the reason of more drastic rising rate of resistance in reset process near Ti electrode.
||Ting Chang Chang - chair|
Yih-Tun Tseng - co-chair
Tai-Fa Young - co-chair
Tsung-Ming Tsai - advisor
Indicate in-campus at 5 year and off-campus access at 5 year.|
|Date of Submission