Defect Characterization in Silicon by Electron-Beam-Induced Current and Cathodoluminescence Techniques

Abstract

This chapter describes electron-beam-induced current (EBIC) and cathodoluminescence (CL) techniques, which have been used for the electrical/optical characterization of extended defects in Si. For these purposes, we use a scanning electron microscope (SEM) for electron beam irradiation. The electric current induced at the internal circuit and light emission from the specimen are used for the imaging of EBIC and CL, respectively. Using these techniques, we have succeeded in classifying the dislocations and grain boundaries (GBs). It is found that the clean dislocations are not so electrically active, but become active after metallic decoration. Large-angle (LA) GBs behave like dislocations. The coherency of GBs and the degree of contamination are the major factors determining the electrical activity of LA-GBs. Small-angle (SA) GBs are different from the former because they have certain carrier recombination activities at room temperature. We may attribute these activities to the bundle of dislocations at the GB plane. Due to such dislocation bundles, SA-GBs emit D-lines and are distinguished in the D-line imaging in CL mode. The SA-GBs are classified by D-lines according to the character and misorientation angle. Now, EBIC/CLs have been extensively used for multicrystalline Si for photovoltaic applications.