Multiferroic characteristics of BiMnO3 thin films offer great prospects to explore, either in terms of ferroelectricity, ferromagnetism, or ferroelasticity. Ferroelectric and ferromagnetic materials can be used in data storage due to their electrical and magnetic properties. Ferroelastic can find its application in microelectromechanical systems devices. This dissertation focused on the synthesis, characterization, and improvement of the multiferroic properties of polycrystalline BiMnO3 thin films as well as the elaborate influence of Cu on the magnetism of BiMnO3 thin films. BiMnO3 films were grown on three different substrates, Si (001), Pt-buffered Si (001), Nb-doped SrTiO3 (100), and also doped with different amounts of Cu. The films were characterized using techniques such as X-Ray diffraction (XRD), scanning electron microscope (SEM), HRTEM observations, by energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, Visible-near-IR spectroscopy (Vis-NIR), electron energy loss spectrometer (EELS), nanoindenter, superconductor quantum interference device (SQUID) magnetometer, and finally, the polarization-electric field (P-E) hysteresis loops of the BiMnO3 thin films were conducted at 200 and 300 K. There are several studies on the growth of thin films, however, they are not clear and in some cases contradictory, therefore, different parameters were controlled during the deposition in terms of working pressure, RF power, substrate, deposition temperature, and target to substrate distance.