  We describe an instrument that exploits the ongoing revolution in synchrotron
sources, optics, and detectors to enable in situ studies of metal-organic vapor
phase epitaxy (MOVPE) growth of III-nitride materials using coherent x-ray
methods. The system includes high-resolution positioning of the sample and
detector including full rotations, an x-ray transparent chamber wall for
incident and diffracted beam access over a wide angular range, and minimal
thermal sample motion, giving the sub-micron positional stability and
reproducibility needed for coherent x-ray studies. The instrument enables
surface x-ray photon correlation spectroscopy, microbeam diffraction, and
coherent diffraction imaging of atomic-scale surface and film structure and
dynamics during growth, to provide fundamental understanding of MOVPE
processes.
