The generation of three-dimensional bipolar transistor models for circuit analysis
by F.-Y. Chang, L. F. Wagner
The results of a two-dimensional bipolar numerical device-analysis program are processed by identifying three regions of the transistor: the intrinsic transistor, the sidewall transistor, and the extrinsic base collector diode. The key parameters which describe each of these regions are extracted using a linking program and fed into a quasi-three-dimensional device analysis program referred to here as the Model Generation Program (MGP). The MGP first generates a large equivalent-circuit distributed network which simulates the three-dimensional geometry of an actual transistor. This distributed network is then analyzed using the existing Advanced Statistical Analysis Program (ASTAP) for circuit analysis. Finally the MGP extracts parameters from the ASTAP analysis to characterize the elements of a lumped-model equivalent circuit, which is then suitable for the circuit design of large-scale integrated circuit chips. The MGP is sufficiently flexible that transistors with a variety of geometries can be generated without repeating the two-dimensional analysis.