• Title/Summary/Keyword: BaTiO$_3$

Search Result 1,475, Processing Time 0.03 seconds

Structural and Electrical Properties of Amorphous 2Ti4O12 Thin Films Grown on TiN Substrate (TiN 기판 위에 성장시킨 비정질 BaSm2Ti4O12 박막의 구조 및 전기적 특성 연구)

  • Park, Yong-Jun;Paik, Jong-Hoo;Lee, Young-Jin;Jeong, Young-Hun;Nahm, Sahn
    • Korean Journal of Materials Research
    • /
    • v.18 no.4
    • /
    • pp.169-174
    • /
    • 2008

  • The structural and electrical properties of amorphous $BaSm_2Ti_4O_{12}$ (BSmT) films on a $TiN/SiO_2/Si$ substrate deposited using a RF magnetron sputtering method were investigated. The deposition of BSmT films was carried out at $300^{\circ}C$ in a mixed oxygen and argon ($O_2$ : Ar = 1 : 4) atmosphere with a total pressure of 8.0 mTorr. In particular, a 45 nm-thick amorphous BSmT film exhibited a high capacitance density and low dissipation factor of $7.60\;fF/{\mu}m2$ and 1.3%, respectively, with a dielectric constant of 38 at 100 kHz. Its capacitance showed very little change, even in GHz ranges from 1.0 GHz to 6.0 GHz. The quality factor of the BSmT film was as high as 67 at 6 GHz. The leakage current density of the BSmT film was also very low, at approximately $5.11\;nA/cm^2$ at 2 V; its conduction mechanism was explained by the the Poole-Frenkel emission. The quadratic voltage coefficient of capacitance of the BSmT film was approximately $698\;ppm/V^2$, which is higher than the required value (<$100\;ppm/V^2$) for RF application. This could be reduced by improving the process condition. The temperature coefficient of capacitance of the film was low at nearly $296\;ppm/^{\circ}C$ at 100 kHz. Therefore, amorphous BSmT grown on a TiN substrate is a viable candidate material for a metal-insulator-metal capacitor.

  • https://doi.org/10.3740/MRSK.2008.18.4.169 인용 PDF KSCI

Geochemical Composition of Volcanic Ash from Historical Eruptions of Mt. Baekdu, Korea (역사시대에 분화한 백두산 화산재의 화학 성분)

  • Yun, Sung-Hyo;Koh, Jeon Seon;Chang, Cheolwoo
    • The Journal of the Petrological Society of Korea
    • /
    • v.27 no.1
    • /
    • pp.37-47
    • /
    • 2018

  • Volcanic ash samples of historical eruptions from Mt. Baekdu were analyzed for major oxides, trace and rare earth elements by a variety of analytical techniques. The results indicate that the ashes consist of approximately 58.8~71.1 wt.% $SiO_2$, 9.6~16.8 wt.% $Al_2O_3$, 4.5~6.9 wt.% $Fe_2O_{3t}$, 0.1~1.7 wt.% MgO, 0.3~1.6 wt.% CaO, 5.2~6.3 wt.% $Na_2O$, 4.3~5.9 wt.% $K_2O$ and less than 1.2 wt.% $TiO_2$. Thirty two trace metals including Ba, Cu, Cr. Co, Ni, Sr, V, Zn, and Zr were analyzed. The ashes can be divided two groups: group A(1 ka Millennium pumice, 1668 and $190{\underline{3}}$ pumice) and group B(1702 pumice) according to the relative enrichment of HREEs. The abundances of heavy metals such as Cu, Co, Mn, and Zn were relatively low. As compared to the Sakurajima volcanic ash, Baekdusan volcanic ash has low concentrations of Y, Nb, Pb, U, Sc, V, Ni and Cu and high concentrations of Zr, Ba, Hf, Cr, Co, Zn and rare-earth (except Eu).

  • https://doi.org/10.7854/JPSK.2018.27.1.37 인용 PDF KSCI