GRAIN-SIZE AND STRAIN IN THIN SPUTTER-DEPOSITED NI0.8FE0.2 AND CU FILMS

The average grain size and strain in the direction parallel to the sur face of thin Ni0.8Fe0.2 and Cu films, sandwiched between Ta layers, ha ve been determined as a function of layer thickness by grazing inciden ce X-ray diffraction. The in-plane grain size and grain size distribut ion were also assessed by plan-view transmission electron microscopy. Standard theta-2 theta X-ray powder diffraction was used to determine the uniform strain in the direction perpendicular to the surface. Both for Ni0.8Fe0.2 and Cu, an elongation of the lattice parameter perpend icular to the surface and a compression of the lattice parameter in th e plane of the film is observed, which decreases with increasing film thickness. Additionally, for Ni0.8Fe0.2 a non-uniform elongation of th e perpendicular interatomic distance at the Ta interfaces is deduced b y fitting a kinematical model to the theta-2 theta diffraction spectru m. This study illustrates the strength and the complementary character of standard powder X-ray diffraction, grazing incidence X-ray diffrac tion and transmission electron microscopy for the structural analysis of thin metal films.