A numerical analysis of transient charge partitioning

The rigorous numerical analysis of charge partitioning in a simple p-n junction structure is presented. Procedures for extracting the relevant terminal charges, based upon the concept of a “pass-through” current, are introduced. The calculation of the pass-through current, the electrostatic displacement current and the (distinct) current associated with the changes in internal charge distributions are described. Methods for dividing the various internal charges into “quasineutral” and “space-charge” components, are also presented. The results obtained by exact analysis are compared with the predictions of the conventional, analytic, charge partitioning models. Significant discrepancies are found to arise from the simplifications necessary for analytic modeling such as the dependence of the partitioning on the ramp speed and injection level and asymmetry between switch-on and switch-off transients. The numerical simulation results offer guidance for the future development of alternative, more accurate, nonquasi-static device models