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 R, are correlated with current crowding phenomena, which can be directly observed by means of emission microscopy.
A new experimental technique for extracting base resistance and characterizing current crowding phenomena in bipolar transistors / Verzellesi, Giovanni; L., Vendrame; R., Turetta; Pavan, Paolo; A., Chantre; A., Marty; M., Cavone; R., Rivoir; E., Zanoni. - STAMPA. - (1992), pp. 413-416. (Intervento presentato al convegno IEEE International Electron Devices Meeting (IEDM) tenutosi a S. Francisco (California, USA) nel Dec. 1992).