A new analytical model and the impact of base charge storage on base potential distribution, emitter current crowding and base resistance

DC emitter crowding effect is modeled analytically for the first time with minority charge storage taken into account. In contrast with previous work that neglected excess carriers, we find that the solution is well behaved without singularity and base voltage pinning. Expressions for base and collector current, large signal and small signal base resistance are also derived. We prove that excess base charge can be monitored using a split base structure. Conductance between the two split base electrodes is a linear function of collector current, independent of emitter current crowding, and its slope is directly proportional to base transit time.<>