Within this work, a set of depositions induced by focused electron beam was prepared. The depositions were prepared in the presence of water vapours from trimethyl(methylcyclopentadienyl)platinum(IV) precursor. The dependence of prepared materials purity on beam accelerating voltage and water vapour pressure was measured. The best platinum content was achieved at (27,2 ± 0,4) at. %, with beam accelerating voltage 5 kV, beam current 1600 pA and water vapour pressure 100 Pa. Due to subsequent long-term exposure to light, air humidity and air oxygen, the platinum content was increased to (39,2 ± 2,1) at. %.