A method for growing a thin film on a substrate of metal or ceramics by beam deposition comprising the steps of:(I) producing from starting gases ions of elements or compounds thereof to be deposited on the substrate;(II) irradiating the ions produced in step (I) with electromagneti waves to electronically excite at least one sort of said ions; and(III) impacting an ion beam comprising the ions excited in step (II) onto said substrate to deposit thereon, thereby growing a film, and an apparatus for practicing the method. The method enables the formation of thin films having a higher crystallinity by electronically exciting ions or neutral species to increase the internal energy thereof and then impacting a beam comprising the excited ions or neutral species onto the substrate.