• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.23-23
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• 2010

The $Bi_2Mg_{2/3}Nb_{4/3}O_7$ (BMNO)-Bi composite films sandwiched by an $Al_2O_3$ protection layer exhibited a linear increase of a dielectric constant with increasing thickness and the 1000nm-thick BMNO-Bi composite films showed a dielectric constant (~220) higher than that of its bulk material (~210), keeping a low leakage current density of about $0.1{\mu}A/cm^2$. An enhancement of the dielectric constant in the BMNO-Bi composite films was attributed to the hybrid model combined by a space charge polarization, dipolar response, and nano-capacitors. On the other hand, 1000nm-thick BMNO-Bi composite films sandwiched by 40nm-thick BMNO layer exhibited a dielectric constant of about 450 at 100 kHz and a leakage current density of $0.1{\mu}A/cm^2$ at 6V.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.20.2-20.2
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• 2011

BMNO dielectric materials with a pyrochlore structure have been chosen and they have quite high dielectric constants about 210 for the bulk material. In the case of thin films, 200-nm-thick BMNO films deposited at room temperature showed a low leakage current density of about $10^{-8}\;A/cm^2$ at 3 V and a dielectric constant of about 45 at 100 kHz. Because high dielectric constant BMNO thin films kept an amorphous phase at a high temperature above $900^{\circ}C$. High dielectric constant BMNO thin films grown at room temperature have many applications for flexible electronic devices. However, because the dielectric constant of the BMNO films deposited at room temperature is still low, percolative BMNO films (i.e., those were grown in a pure argon atmosphere) sandwiched between ultra-thin BMNO films grown in an oxygen and argon mixture have greater dielectric constants than standard BMNO films. However, they still showed a leakage problem at a high voltage application. Accordingly, a new nano-structure that uses BMNO was required to construct the films with a dielectric constant higher than that of its bulk material. The fundamental reason that the BMNO-Bi nano-composite films grown by RF-Sputtering deposition had a dielectric constant higher than that of the bulk material was addressed in the present study. Also we used the graphene as bottom electrode instead of the Cu bottom electrode. At first, we got the high leakage current density value relatively. but through this experiment, we could get improved leakage current density value.