AbstractLarge area transmission and section topographs of semi-insulating gallium arsenide wafers grown by the gradient freeze technique are made with synchrotron radiation at HASYLAB in Hamburg and at ESRF in Grenoble. Several high-resolution images including stereo pairs are obtained on the same film at a time. A typical dislocation line is an arc of a circle which starts from one surface and ends at the same surface. From the disappearance of the dislocation image and using the g · b = 0 criterion it is concluded that the Burgers vector b of the most common dislocations is parallel to 〈110〉. Rather large volumes of the wafer are dislocation-free. Section topographs of epitaxial wafers show defects and strain fields at the interface between an n-type substrate and the epitaxial layers grown by chemical vapor deposition. The results are compared with those obtained from detector performance measurements.

Tuomi, T., Juvonen, M., Rantamäki, R., Hjelt, K., Bavdaz, M., Nenonen, S., Gagliardi, M.-A., Mcnally, P. J., Danilewsky, A. N., Prieur, E., Taskinen, M., & Tuominen, M. (1997). Synchrotron x-Ray Topographic Study Of Dislocations In Gaas Detector Crystals Grown By Vertical Gradient Freeze Technique. MRS Proceedings, 487.