Crystalline β-C3N4 films deposited on metallic substrates by microwave plasma chemical vapor deposition

Carbon nitride films were grown on poly-crystalline metallic substrates, such as Ta, Mo and Pt, by the microwave plasma chemical vapor deposition (MPCVD) method. The deposited films were examined by scanning electron microscope (SEM), energy dispersive X-ray (EDX) and XRD. SEM observations show that the films deposited on Pt substrates consisted of small crystalline grains, while the morphology of the films on the other substrates were irregular. X-ray diffraction experiments show that metallic carbide or nitride are formed in films deposited on Ta and Mo but not on Pt substrates. However, characteristic peaks of crystalline β-C3N4 and α-C3N4 can be seen in films deposited on all three substrates. EDX analysis show that N/C ratios can be as high as 4/3 for carbon nitride films deposited on Pt under optimized growth conditions.