3-DIMENSIONAL SITE DEPENDENCE OF SINGLE-ION-INDUCED CHARGE COLLECTIONAT A P-N JUNCTION-ROLE OF FUNNELING AND DIFFUSION-PROCESSES UNDER DIFFERENT ION ENERGY

The amount of charges induced by high energy single ion irradiation at a p-n junction diode has been measured and its dependence on the ion incident position has been evaluated by using single-ion microprobe te chnique. By irradiating single He ions with various incident energy (1 .4-4.05 MeV), dependence of the profiles of collected charges on the i on incident energy has been investigated. Origins of the different pro files among the different incident energy are discussed in terms of di fferent contribution of two mechanisms of charge collection, namely, f ield funneling and diffusion of carriers. In the case of the ion incid ence within the junction area, dependence of the charge collection pro file on the ion incident energy comes from different contribution of t he funneling in the charge collection process, while difference in the collection efficiency of the diffused charges affects the profile in the case of the ion incidence at outside of the junction. (C) 1998 Ame rican Institute of Physics.