[en] The quality of semiconductor p-n junctions and substrates is essential for a reliable performance of microelectronic devices. The imaging techniques of ion beam induced charge (IBIC) and ionoluminescence (IL) are applied to image and analyze light emitting diodes (LEDs). The LEDs have been imaged both from the front (beam normal to p-n junction plane) and from the transverse direction (beam parallel to p-n junction plane). The imaging techniques provide details on the structural uniformity of the p-n junction and the light emitting properties, as stimulated by proton irradiation. Following IBIC and IL analysis, PIXE and RBS provide elemental distribution information on the metal layers and other components in the LEDs. The techniques which can be utilized by the nuclear microprobe potentially provide powerful tools for the failure analysis and quality control of the fabrication of microelectronic devices