  Solid-phase epitaxy (SPE) and other three-dimensional epitaxial
crystallization processes pose challenging structural and chemical
characterization problems. The concentration of defects, the spatial
distribution of elastic strain, and the chemical state of ions each vary with
nanoscale characteristic length scales and depend sensitively on the gas
environment and elastic boundary conditions during growth. The lateral or
three-dimensional propagation of crystalline interfaces in SPE has nanoscale or
submicron characteristic distances during typical crystallization times. An in
situ synchrotron hard x-ray instrument allows these features to be studied
during deposition and crystallization using diffraction, resonant scattering,
nanobeam and coherent diffraction imaging, and reflectivity. The instrument
incorporates a compact deposition system allowing the use of
short-working-distance x-ray focusing optics. Layers are deposited using
radio-frequency magnetron sputtering and evaporation sources. The deposition
system provides control of the gas atmosphere and sample temperature. The
sample is positioned using a stable mechanical design to minimize vibration and
drift and employs precise translation stages to enable nanobeam experiments.
Results of in situ x-ray characterization of the amorphous thin film deposition
process for a SrTiO3/BaTiO3 multilayer illustrate implementation of this
instrument.
