THIN FILM XRD TOTAL PATTERN FITTING （薄膜XRD总模式拟合）.pdf

Copyright ©-International Centre for Diffraction Data 2010 ISSN 1097-0002 112 THIN FILM XRD TOTAL PATTERN FITTING APPLIED TO STUDY OF EVOLUTION OF MICROSTRUCTURE OF TiO2 FILMS R. KuZ. Mat, L. Nichtov Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, 121 16 Praha 2, Czech Republic ABSTRACT New XRD total pattern fitting software MStruct was used in study of crystallization and micro- structure evolution of magnetron-deposited TiO2 thin films and powders. It is an extension of the FOX program for structure determination from powder diffraction and it includes in particular the effects and corrections necessary for thin film analysis when parallel beam geometry and asymmetric detector scan at small angles of incidence are applied (corrections for refraction and absorption, residual stress, preferred orientation). The program also includes description of crys- tallite size broadening in terms of log-normal distribution, two models of strain (phenomenologi- cal and dislocation model) as well as the influence of stacking faults in the most common cubic and hexagonal structures. It was shown that during crystallization of amorphous TiO2 films, ten- sile stresses are generated which cause anisotropic shifts of diffraction peaks and the considera- tion of the effect in terms of weighted Reuss-Voigt model improved the fits significantly: The determined stresses agree well with the values measured directly by stress analysis. The crys- tallite size determined was above 100 nm already from the very beginning of crystallization proc- ess in contrast to nanocrystalline films (5-10 nm) which were stable to much h