On the deionization of impurities as an explanation for excess intrinsic carrier density in heavily doped silicon

The recent models of Heasell and Popovic are discussed from the unifying viewpoint that both use the deionization of impurities to try to explain the excess intrinsic carrier density (or deficit effective doping concentration) experimentally observed in heavily doped silicon. The conclusion is that neither of these models can explain the experimental data. Thus neither satisfactorily replaces the interpretation given earlier that attributes the experimental findings to energy-bandgap narrowing. From the standpoint of device analysis, this conclusion bears on the models used to explain the experimental result that the common-emitter current gain in silicon bipolar transistors and the open-circuit voltage in silicon solar cells are often much lower than predicted by classical theory.