An accurate design method of bipolar devices using a two-dimensional device simulator

The systematic application of two-dimensional analysis for the bipolar device design is described. In this analysis, surface recombination is taken into account by properly modifying the carrier lifetime term, in addition to mobility variations and bandgap narrowing effects. Moreover, an effective method to obtain terminal currents from the calculated current densities is introduced. The analysis of transistors with different emitter length demonstrates the validity of this procedure. The propagation delay time of IIL also is calculated usingV-Icharacteristics and capacitances obtained by this two-dimensional analysis. The results give good agreement with experimental ones. IIL and SFL with subnanosecond gate delay time are designed with the suitable geometry and doping profiles by the two-dimensional analysis.