AVS 52nd International Symposium
    Thin Films Wednesday Sessions
       Session TF-WeA

Paper TF-WeA8
Texture Evolution during Shadowing Growth of Ru Nanorods

Wednesday, November 2, 2005, 4:20 pm, Room 306

Session: Fundamentals of Thin Films
Presenter: F. Tang, Rensselaer Polytechnic Institute
Authors: F. Tang, Rensselaer Polytechnic Institute
T. Karabacak, Rensselaer Polytechnic Institute
G. Churamani, Rensselaer Polytechnic Institute
G.-C. Wang, Rensselaer Polytechnic Institute
T.-M. Lu, Rensselaer Polytechnic Institute
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A detailed study of texture evolution during oblique angle deposition of ruthenium vertical nanorods by dc magnetron sputtering is presented. The Ru nanorods have diameters less than 130 nm and lengths ranging from ~ 40 to ~ 480 nm. We used reflection high energy electron diffraction (RHEED) to characterize texture and demonstrated that RHEED can be a powerful tool to follow the growth front of texture evolution. The diffraction patterns showed that the nanorods developed into a strong vertical (100) texture unlike the usually observed (002) texture of conventional Ru films grown by normal incidence deposition. Furthermore, through the quantitative analysis of the RHEED patterns, it was found that the dispersion angle, @Delta@@theta@, of the texture evolved into a power law relationship with respect to time t before its saturation, @Delta@@theta@ ~ t@super p@, where p = - 0.49 ± 0.01. This is shown for the first time that the power law relationship exists not only in the process of morphology evolution but also texture evolution under oblique angle deposition. The analyses of SEM and TEM images reveal the column competition growth, column dispersion, and the single crystal structure of the individual nanorod. We correlate the evolution of column dispersion angle to the evolution of the texture dispersion angle. We also simulated the evolution of the column dispersion angle based on a modified needle model. The exponent of the power law relationship obtained from the simulation was consistent with experimental value and almost independent of the initial simulation conditions, which may indicate a universal scaling behavior. *F.T. is the recipient of the Harry Meiners Fellowship.