Real-time in situ x-ray diffraction as a method to control epitaxial growth

We developed a real-time in situ x-ray Bragg diffraction technique for monitoring epitaxial growth. In our setup, the x-ray diffraction requirement of an extremely exact sample adjustment and an angular scan of sample and detector are circumvented by using a slightly divergent x-ray beam and observing an extremely asymmetric Bragg reflection with a multichannel detector. The angular range covered by the stationary multichannel detector corresponds nearly exactly to the q(z) interval of a conventional omega-2theta scan. The technique is demonstrated by monitoring the molecular-beam epitaxial growth of a ZnSe epilayer on (001)GaAs. The exposure time of each diffraction pattern is only a few seconds, which enables a real-time x-ray diffraction monitoring of the epitaxial growth process. (C) 2003 American Institute of Physics.