It is well known that heat treatment induced plastic deformation of GaAs substrates is a key factor that reduces the yield of electronic devices in manufacturing processes on an industrial scale. Our recent X-ray topographic survey showed that a quite common, radiatively heated, non In-bonded sample holder design can cause severe plastic deformation in two-inch diameter GaAs (001) substrates when they are heated up to about 650 °C in a molecular beam epitaxy (MBE) growth chamber. Unintentional plastic deformation occurred for all three investigated MBE machines, which were of different make, but we overcame the technical problem by modifications to the sample holder of a user built MBE machine. At present, however, there is no theoretical model available that can satisfactorily describe the experimental observations including the spatial distribution of the majority of the dislocation bundles.

The plastic deformation up to about 98 % is realised by bundles of dislocations which start at the sample edges around the four <100> peripheral areas,