  To obtain crystalline thin films of alpha-Quartz represents a challenge due
to the tendency for the material towards spherulitic growth. Thus,
understanding the mechanisms that give rise to spherulitic growth can help
regulate the growth process. Here the spherulitic type of 2D crystal growth in
thin amorphous Quartz films was analyzed by electron back-scatter diffraction
(EBSD). EBSD was used to measure the size, orientation, and rotation of
crystallographic grains in polycrystalline SiO2 and GeO2 thin films with high
spatial resolution. Individual spherulitic Quartz crystal colonies contain
primary and secondary single crystal fibers, which grow radially from the
colony center towards its edge, and fill a near circular crystalline area
completely. During their growth, individual fibers form so-called rotational
crystals, when some lattice planes are continuously bent. The directions of the
lattice rotation axes in the fibers were determined by an enhanced analysis of
EBSD data. A possible mechanism, including the generation of the particular
type of dislocation(s), is suggested.
