Single Transistor-Based Methods for Determining the Base Resistance in SiGe HBTs: Review and Evaluation Across Different Technologies

The base series resistance is an important parameter for bipolar junction transistors and heterojunction bipolar transistor (HBTs). Although many methods have been proposed for its experimental determination, their results vary significantly. In this paper, the most widely used methods are reviewed and applied to SiGe HBTs of different technologies and generations including different device types, i.e. high-speed and high-voltage SiGe HBTs. The accuracy of the methods is evaluated by applying them to a sophisticated physics-based compact model, allowing to clearly detect and explain the causes for the observed inaccuracies or failures. The methods are then also applied to experimental data. In both cases, a large variety of device sizes have been investigated. This paper and its results provide insight into each method's accuracy, its application limits with respect to a technology, device size, and operating range as well as its requirements in terms of equipment and extraction effort.