Ion-beam-assisted deposition of tin thin films

X-ray diffraction and transmission electron analyses are used to investigate changes in the microstructure that occur when TiN films are grown by sequential deposition and irradiation on unheated Si substrates. A N2-Ar gas mixture serves partly for the reactive sputter deposition of TiN from Ti in a rf magnetron target and partly for the generation of a broad ion beam in a Kaufman source. When analyzed in terms of a simple model, the data suggest the existence of a critical growth rate of two Oil) bilayers of TiN per deposition-irradiation cycle. Below that rate, the columnar growth microstructure changes into a granular one with azimuthal texture.