Microstructure of thin iron carbide films prepared in a glow discharge

Thin (50–80 nm) iron carbide films were grown on carbon-coated copper grids in an r.f. glow discharge using iron pentacarbonyl and hydrogen as starting materials. The substrate temperatures were varied in the range 200–500 °C. The microstructure and phases present in these films are compared with the corresponding results previously obtained by X-ray diffraction, atomic force microscopy, scanning electron microscopy and Auger electron spectroscopy for thick (200–1100 nm) films grown on glass substrates. Transmission electron microscopy studies show that the 50–80 nm films contain a mixture of phases at all deposition temperatures. Transmission electron micrographs of annealed films and films deposited at high temperatures show a clear indication of grain growth.