Energy-filtered electron diffraction, X-ray photo-electron spectroscopy, electron energy-loss spectroscopy, field emission scanning electron microscopy and X-ray diffraction techniques were used to establish that O impurities which were incorporated into magnetron-sputtered W films played a dominant role in the formation of the stacking-faulted A15 structure. The latter structure was found to be a mixed phase which consisted of ordered and stacking-fault W3W structures. The effect of O in stabilizing the stacking-faulted A15 structure was also clarified by in situ annealing.

Structure and Properties of Stacking Faulted A15 Tungsten Thin Films. Y.G.Shen, Y.W.Mai: Journal of Materials Science, 2001, 36[1], 93-8