Asymmetrical strain distribution in sputtered TiN layers

Abstract

The strain and texture in magnetron sputtered TiN layers were investigated by means of X-ray diffraction. The results indicated either a fiber or a biaxial texture of the specimens. In a fiber texture, there is only a preference for the plane that grows parallel to the interface and for the biaxial texture, there is a preferential growth direction within this plane. The components of strain in the samples are determined and the measured strain shows that in the samples with a fiber texture there is no dependence on the angle φ. This is different for the biaxial texture samples, i.e. changing φ changes the strain. The strain in the fiber and biaxial textured samples are due to the same origin; thermal strain and a strain due to the atomic peening process. This results in a rotationally symmetric biaxial strain field (strain tensor in the sample system has only two relevant components, ε 11 and ε 22, and these are equal). Consequently the difference in strain distribution can only be due to the difference in texture. Indeed there appears to be a relation between strain distribution and texture in these specimens via the high anisotropy in the elastic compliance of TiN.