Germanium and silicon monocrystals with controlled grown‐in medium‐angle grain boundaries and crystals with isolated dislocations are subjected to a scanning electron beam (SEB) with simultaneous application of a bias field in a transversal direction. Amplification of the induced current signals and oscillographic display reveals clearly the extended space charge of defects and the junction behavior of a two‐dimensional array of edge dislocations with a radius of the space‐charge pipe from a few microns to 25 microns.