Mk Jeon

Electrical properties of Bi2Mg2∕3Nb4∕3O7 (BMN) pyrochlore thin films deposited on Pt and Cu metal at low temperatures for embedded capacitor applications

200-nm-thick BMN films were deposited on Pt∕TiO2∕SiO2∕Si and Cu∕Ti∕SiO2∕Si substrates at various temperatures by pulsed laser deposition. The dielectric constant and capacitance density of the films deposited on Pt and Cu electrodes show similar tendency with increasing deposition temperature. On the other hand, dielectric loss of the films deposited on Cu electrode varies from 0.7% to 1.3%, while dielectric loss of films on Pt constantly shows 0.2% even though the deposition temperature increases. The low value of breakdown strength in BMN films on Pt compared to films deposited on Cu electrode was attributed to the increase of surface roughness by the formation of secondary phases at interface between BMN films and Pt electrodes.

Effect of thickness on electrical properties of bismuth-magnesium niobate pyrochlore thin films deposited at low temperature

Bi2Mg2∕3Nb4∕3O7 (BMN) pyrochlore thin films were deposited at 25 and 100°C on Cu∕Ti∕Si substrates by pulsed laser deposition. Dielectric and leakage current properties of BMN films are investigated as a function of film thickness. The critical thicknesses showing the thickness dependence of dielectric constant are approximately 50 and 70nm in BMN films deposited at 25 and 100°C, respectively. The capacitances of interfacial layers in the films deposited at 25 and 100°C are approximately 5.5 and 3.9pF, respectively. The thickness dependence of leakage current characteristics was attributed to the copper diffusion into the BMN films. An intrinsic conduction of BMN films was controlled by Schottky emission and the barrier height was estimated as 0.9–1.2eV in the temperature range from 25to100°C. Film thickness in terms of leakage current characteristics is limited above 100nm for embedded capacitor applications.

Improvement of Leakage Current Characteristics by Plasma Treatment in Bi2Mg2 ∕ 3Nb4 ∕ 3O12 Dielectric Thin Films

Bismuth magnesium niobate (BMN) thin films deposited on Cu/Ti/Si substrates at 100°C by pulsed laser deposition were investigated for the effect of plasma treatment on dielectric and leakage current characteristics. The dielectric constant and dissipation factor of 60 nm thick films slightly decrease with increasing oxygen content in atmosphere of plasma treatment. The leakage current densities were improved with increasing oxygen content. The capacitance density and breakdown voltage of the films treated with N 2 :O 2 = 100:100 seem (standard cm 3 /min) were approximately 520 nF/cm 2 and 3 V, respectively. On the other hand, 100 nm thick BMN films treated by plasma at N 2 :O 2 = 100:100 sccm exhibit a leakage current density of approximately 6 X 10 -7 A/cm 2 at 10 V and a breakdown voltage above 10 V which is possible for embedded capacitor applications.