Analysis of the Transistor Tetrode-Based Determination of the Base Resistance Components of Bipolar Transistors—A Review

The base series resistance is a very important parameter for bipolar transistors. In this paper, methods for its determination from tetrode structures are analyzed and quantitatively evaluated in terms of their accuracy and suitability for advanced SiGe HBTs. The accuracy of the methods is evaluated based on 2-D device simulation, thus allowing to clearly detect and explain the causes for observed inaccuracies or failures of a method. The methods are then applied to experimental data. It is shown that one of the methods yields reliable and accurate results over a wide bias range, while the other two are limited either in accuracy or to ${V}_{\text {CE}} = {0}\,\,\text {V}$ .