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이극성 저항변화 메모리 소재의 전기적 • 분광학적 분석을 통한 저항변화 메모리 소자의 구동 메커니즘 연구

Title
이극성 저항변화 메모리 소재의 전기적 • 분광학적 분석을 통한 저항변화 메모리 소자의 구동 메커니즘 연구
Other Titles
Switching mechanism study of RRAM device by electrical • spectroscopic analysis of bipolar resistive memory material
Author
김종윤
Alternative Author(s)
Kim, Jong Yun
Advisor(s)
윤태현
Issue Date
2017-08
Publisher
한양대학교
Degree
Doctor
Abstract
The goal of this thesis is to clarify the switching mechanism of resistive random access memory devices by electrical • spectroscopic analysis of bipolar resistive materials. Therefore, this paper consists of fabricating resistive random access memory with different resistance materials in Al/resistive material/Al structure, and clarifying the switching mechanism by electrical characteristic analysis and spectroscopic analysis. In the first part, the active material in the Al/resistive materials/Al structure was made into organic material PEDOT:PSS. The measured I-V characteristics of the fabricated memory device showed the electrical characteristics of the bipolar resistive random access memory. And, electrical characteristics were analyzed and it was found that it was driven by space charge limited current. For the analysis of the mechanism of the memory device, the memory device was measured by TEM and XPS. TEM and XPS measurements confirmed that the top interface layer of Al-S and Al-O was formed. The memory device of Al/PEDOT:PSS/Al structure is switched by trapping/detrapping of charge due to insulator top interface layer (Al-S and Al-O). In the second part, the active material in the Al/resistive materials/Al structure was fabricated using TiO2, a metal oxide. The measured I-V characteristics of the fabricated memory device showed the electrical characteristics of the bipolar resistive random access memory. And, electrical characteristics were analyzed and it was found that it was driven by space charge limited current. However, these memory devices were switched in different type. In-situ analysis using scanning transmission X-ray microscopy was performed to analyze the mechanism of the memory device. In the first case, it was found that a region of high reduction on the TiO2 film was formed by electroforming, and the conduction filaments were formed or destroyed by the oxygen vacancy in the region. In the second case, the insulating (Al-Ti-O) layer is formed at the top interface between the Al top electrode and the TiO2 film, and it is confirmed that the insulating (Al-Ti-O) layer is switched due to the increase/decrease of the insulating (Al-Ti-O) layer serving as the charge barrier. In the third part, the active material in the Al/resistive materials/Al structure was fabricated using a graphene oxide (GO). The measured I-V characteristics of the fabricated memory device showed the electrical characteristics of the bipolar resistive random access memory. And, electrical characteristics were analyzed and it was found that it was driven by space charge limited current. In-situ analysis using scanning transmission X-ray microscopy was performed to analyze the switching mechanism of the memory device. The AlO layer is formed on the top interface between the Al top electrode and the GO film, and the GO film is oxidized/reduced according to the current flow, thereby causing the increase and decrease of the AlO layer. Only the hydroxyl, epoxy, and carboxyl groups in the GO film affected the increase and decrease of the top interface layer. The memory device of Al/GO/Al structure was confirmed to be switched by increasing/decreasing the charge barrier due to the oxidation/reduction of the top interface layer serving as a charge barrier.
URI
http://hdl.handle.net/20.500.11754/33734http://hanyang.dcollection.net/common/orgView/200000431517
Appears in Collections:
GRADUATE SCHOOL[S](대학원) > THEATER & FILM(연극영화학과) > Theses (Master)
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