| Abstract: | ![]()
Everhart a. o. described a sentitive method of observing pn-junctions in semiconductor devices. When a semiconductor is bombarded by high energy electrons, electron hole pairs are generated within the bulk material. If the minority carriers cross the pn-junction before recombining, an electron beam induced signal (EBIC-signal) results with the maximum at the deplation region. If the charge carrier are generated in a distance larger than a few diffusion lengths from the junction, recombination will occur with little or no contribution to the output signal. At first a theoretical interpretation is given of the connection between the distribution of the space charge and an inverse voltage in the deplation layer of barrier in dependence on impurity density. It is followed by a mathematical method for careful analysis of the slopes and the amplitude of the EBIC-signal. The results were compared with the theorie. So it is possible to obtain informations on the profile of impurity density in the specimen. The use of the scanning technique with brightness modulation by the EBIC-signal allowed the demonstration of inhomogeneities in the diffusion front. |
