III-V semiconductors like gallium arsenide (GaAs) are important materials for opto- and microelectronics, nano-technology, as well as sensors for X-ray detectors. For these applications, any crystalline imperfection has a potential impact on device yield and performance. As shown by nm-scale TEM studies, so-called glide prisms play a crucial role during plastic deformation of such compound materials. Taking advantage of recent progress in both X-ray diffraction imaging methodology and suitable quasi in situ sample environments, in this proposal we aim at the 3D characterization of glide prisms in GaAs wafers, for the first time following their formation and subsequent evolution on the length scales between μm and mm, and under thermo-mechanical loads as typical of microelectronic device production and processing.