A simple estimate of funneling-assisted charge collection

Funneling is qualitatively discussed in detail, and a quantitative analysis is given for the total (time-integrated) collected charge. It is shown that, for an n/sup +//p junction, the total collected charge Q/sub T/ is given by QT=(1+ mu /sub n// mu /sub p/) Q/sub D/+2Q/sub diff/, where Q/sub D/ is the charge initially liberated in the depletion region and Q/sub diff/ is charge collected by diffusion. This equation does not apply to very short ion tracks or to devices having a thin epilayer. A numerical example is presented, and a comparison is made with PISCES results.<
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