Influence of Collector Design on the SiGe HBT's Quasi-Saturation Characteristics

In this paper we examine the SiGe HBT's current-voltage characteristics where J_c is several times the Kirk current density J_HC = qN_epi v_sat. We analyze the QS characteristics by comparing the NPN's with different intrinsic collector doping profiles fabricated on the same wafer. Data from NPN's made from various thicknesses and concentrations of the epi-layer are also presented