Generalized Early Voltage Model of Bipolar Transistors for Linearly Graded Germanium in Base
The standard Early voltage of the SPICE Gummel-Poon model (SGP) is generalized for SiGe npn heterojunction bipolar transistors (HBTs). An accurate model for Early effects compatible with the SGP model is obtained considering graded germanium induced bandgap narrowing effect in the base in modern SiGe HBTs and simplified to a compact model which is consistent with ISE TCAD simulation results. The presentation of the Early effect model is significant for the design and simulation of the high performance SiGe BiCMOS technology.
X. B. Xu et al., "Generalized Early Voltage Model of Bipolar Transistors for Linearly Graded Germanium in Base", Applied Mechanics and Materials, Vols. 110-116, pp. 3311-3315, 2012