The resistive switching behavior of Al/ZnO/Al layered memory device structures was investigated in connection with varying ZnO layer thickness and related changes in crystallinity and concentration of oxygen-related defects. It was observed that, with increasing thickness, the crystallinity of the ZnO layer was improved and the concentration of oxygen-related defects within the layer increased. While the device showed unipolar switching characteristics, the currentvoltage hysteresis was dependent on the thickness of the ZnO layer. In particular, the set voltage gradually increased with increasing layer thickness in the high resistive state whereas the reset voltage remained almost constant in the low resistive state. The observed operation characteristics of the device structures in relation to the crystallinity and oxygen-related defect concentration of the ZnO layer suggest that extended defects such as grain boundaries and dislocations play important roles in determining device performances.
Bibliographical noteFunding Information:
This work was supported by WCU (World Class University) program through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology ( R32-20031 ), and the academic–industrial cooperation program funded by Hynix Semiconductor Inc. ( 2008-8-0306 ).
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Materials Chemistry