Scalable large-signal model for SiGe HBTs

In this article, a scalable large-signal model for SiGe heterojunction bipolar transistors (HBTs) is presented. Compared with SPICE Gummel-Poon model, the proposed model has taken into account the self-heating effects, which is important for large-signal operations. The model includes a new base-collector breakdown description, which has taken the current dependence into account. This model allows exact modeling of all transistor parameters from single emitter size cells to other size devices. The scaling rules are shown in detail. The model is verified by the SiGe HBTs with emitter area of 0.3 × 20.3, 0.3 × 13.9, 0.3 × 9.9, and 0.3 × 1.9 um ². Excellent agreement has been achieved between modeled and measured data over a wide range of bias conditions and signal frequencies. The model has been implemented in Verilog-A using the ADS circuit simulator.