Published online by Cambridge University Press: 06 March 2019
White beam transmission topography was used to image defect structures in gallium arsenide single crystal substrates representative of those used for microwave integrated circuit fabrication. A scanning topographic camera was developed for Beamline X-19C at the National Synchrotron Light Source. Acquiring film topographs within a particular range of scan rates and x-ray fluxes was found to produce distorted images. The distortions were shown to be thermoelastic, arising from inhomogeneous deposition of thermal energy through the absorption of residual x-rays. The problem could be circumvented using faster scans with some sacrifice in spatial resolution. Real time electrooptic topographs were recorded using x-ray fluxes about one percent of those used for the film topographs. The potential for reducing the flux requirement to even lower levels which would be accessible to flash x-ray generators is considered.