Bismuth magnesium niobate (BMN) thin films deposited on Cu/Ti/Si substrates at 100 degrees 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 sccm (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. (c) 2007 The Electrochemical Society.