Texture of NiSi films on Si(001), (111), and (110) substrates

Abstract

Synchrotron radiation was used to study the texture of poly-crystalline NiSi films that were formed by a solid state reaction between a 30 nm Ni film and Si(001), (111), and (110) substrates. All films were strongly textured, and the different texture components were identified. Apart from the spots and/or circles characteristic of epitaxy or fiber texture, the pole figures contained symmetrical, though complex, patterns of lines. These lines are characteristic of axiotaxy, whereby NiSi grains preferentially align their (211)- or (202)-type planes parallel to Si(110)-type planes in each of the substrates. Since the spacing between NiSi(211) or NiSi(202) planes is almost identical to the spacing of 1.920 Å between Si(220) planes, the alignment of these planes results in a boundary structure that is periodic along a single direction in the plane of the interface. Intensity variations along the lines on the pole figures are also explained by the degree of periodicity of the interface. The brightest spots on the lines correspond to interface structures for which periodicity is achieved along two independent directions within the plane of the interface.