X-ray photoelectron spectroscopy study of the role of nitrogen in FeSiAl„N... reactive sputtered films

Nitrogen has a profound effect on the stress, nanostructure, and magnetic properties of FeSiAl~N! reactive sputtered films. X-ray photoelectron spectroscopy is an excellent tool to investigate the role of N in these films, since it provides both compositional and chemical bonding information simultaneously. The N is observed to first combine with the Al in the films. For increasing amounts of N, increasing amounts of Al as nitride are observed. Then at the point that the Al is all nitride, the N starts to combine with Si. It is in this region that an abrupt change is observed in magnetic properties, stress, and nanostructure. For low N, the films consist of single phase 100-nm-diam bcc grains; after the transition, films consist of a two phase nanostructure of 10-nm-bcc grains in an amorphous matrix. The N content of the films also increases sharply at this point. The addition of N to the sputtering plasma also causes changes in the apparent relative sputtering yields at these higher N levels: Fe content of the films decreases considerably, while Al and Si percentages show modest increases. This can help explain why the saturation magnetization (M s) has been observed to decrease with increasing N in the plasma, for these higher N levels. © 2002 American Institute of Physics. @DOI: 10.1063/1.1453949#