A new experimental technique for extracting base resistance and characterizing current crowding phenomena in bipolar transistorsInternational Technical Digest on Electron Devices Meeting

A new DC technique for extracting parasitic base resistance, RB, of advanced bipolar transistors is described. The technique is based on impact-ionization-induced base current reversal and enables RB to be measured as a function of collector-base voltage and of emitter current. To obtain accurate results, the influence of the Early effect on the emitter-base voltage at constant emitter current must be accounted for. Measured values of RB are correlated with current crowding phenomena, which can be directly observed by means of emission microscop