CHARACTERIZATION OF LEC GAAS BY ELECTRON-BEAM-INDUCED CURRENT ANALYSIS

Some considerations are presented to show that the currently used mode ls of electron beam induced current (EBIC) contrast at dislocations ar e not sufficient to analyse fully complex defect structures such as ve ry large impurity clouds in LEC GaAs. These large impurity clouds were therefore investigated by the energy dependent EBIC method. In this w ay the involvement of the shallow dopant impurities can be established . It is stressed that, because of the pronounced s short-range inhomog eneous distribution of impurities and dislocations in bulk LEC GaAs cr ystals, the energy dependent EBIC method in planar geometry is a very efficient method for investigating such crystals since it has a very h igh spatial resolution and allows determination of the shallow dopant density.