Mechanism of texture formation in submicron Cu thin films

Abstract

We successfully fabricated the submicron Cu thin films with different texture components and thicknesses by magnetron sputtering method, and investigated the underlying mechanism of texture formation. The X-ray diffraction, electron backscatter diffraction and transmission electron microscopy were employed to elucidate the {111}, {011}, {001} and random texture components formation mechanism. In addition, the orientation factors were calculated to clarify the influencing mechanism of grain preferential growth in the yielding submicron Cu thin films. The film sputtered at 100 W has a preponderance growth of {111} oriented grains, which is explained by the minimum of surface energy theory. With sputtering power increased to 200 W, the formation of random texture could be attributed to the presence of extensive twinning. Increase the sputtering power to 300 W and simultaneously keep the thickness to 200 nm, then the texture transforms to {001} texture component. Further increased the thickness to 1000 nm, the fraction of {011} texture component reveals preponderantly, which is controlled by the differences of orientation factors during yield process. The qualitative coincidence between the experimental results and theoretical analysis indicated that the underlying mechanism of preferential growth in the submicron Cu thin films was related to the competition of different driving forces. From adjusting the major driving force, different texture components could successfully be manipulated in submicron Cu thin films.