An improved parameter-extraction method of SiGe HBTs' substrate network

In this letter, an improved method for substrate network parameter extraction of SiGe heterojunction bipolar transistors (HBTs) is proposed. It is found that, without taking the intrinsic circuit elements into consideration, the conductance of substrate network will be underestimated while the susceptance of substrate network will be overestimated. Therefore, an iteration procedure is developed,to determine the intrinsic circuit elements of SiGe HBTs first. The intrinsic circuit elements are then applied to remove their influence on the substrate network parameter extraction. Compared with the conventional method, the proposed one can avoid some unphysical modeling results and provide reliable substrate network parameters.