Process Development of BiFeO3 thin films for non-volatile Resistive Random Access Memory

• Main Authors: Chih-Cheng Yu, 游志誠
• Other Authors: Jian-Yang Lin
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/06992275045789029373

碩士 === 國立雲林科技大學 === 光學電子工程研究所 === 99 === Recently, advances in technology, people dependence on electronic products, increasing. The memory were used in electronic products, therefore, the wealth of researches have been proceed for the nonvolatile memories. The conventional floating gate memory are expected to reach certain technical and physical limit in the future, the charges could be leaked by the tunnel oxide layer when device be operated. Hence, the new generation non-volatile memories have been developed. Resistive Random Access Memory (RRAM) are simple structure in process, lower consumption of energy, higher operating speed, high endurance, high-density integration, and non-destructive read, etc. RRAM might be expected to replace the memory of conventional floating gate. In this paper, we will study resistive switching for the device of platinum / bismuth ferrite / titanium nitride (Pt/BiFeO3/TiN) and discuss material of bismuth ferrite at RRAM characteristics. This research can be categorized into several parts included impact flow of Oxygen gas or not, multi-bits storage for unit cell, constant current stresses, temperature effect, declined operation current and analysis of material. By exploiting these few kinds of devices and measurement skills, we can investigate the bulk switching behavior, the paths was form, and redox in the resistive switching layer when resistive switching occurs. We propose a model to explain the phenomenon which was observed in experiment, and analysis material in our experiment. Moreover, we investigate the multi-level feasibility of Pt/BiFeO3/TiN structure. It is reported that using On-states as multi-level is suitable than Off-states. Furthermore, Pt/BiFeO3/TiN structure exhibits prominent resistive switching behavior. Both low resistance (ON state) and high resistance (OFF state) are stable and reproducible during a successive resistive switching by using a DC voltage sweeping. The resistance ratio of ON and OFF state is over 1000 times. The retention properties of both states are also very stable. Finally, we conclude that Pt/BiFeO3/TiN has promising potential in the next-generation non-volatile memory.