Hybrid two-section model for the small-signal current crowding effect in SiGe HBTs

A two-section equivalent circuit model with hybrid topology is proposed to model the base impedance of SiGe HBTs. The formulations suitable for implementation in compact-model are obtained. A simpler yet accurate method is also proposed to implement the hybrid two-section model. The models are implemented in Verilog-A and small-signal simulations are carried out. The proposed models predict the small-signal lateral NQS effect more accurately than the existing models.