Methods for Determining the Collector Series Resistance in SiGe HBTs—A Review and Evaluation Across Different Technologies

Many methods have been proposed for the experimental determination of the collector resistance in bipolar junction transistors and HBTs. In this paper, the most widely used methods are reviewed and applied to SiGe HBTs with a large variety of device sizes fabricated in different technologies and generations, including high-speed and high-voltage transistors. First, the accuracy of those methods, which are based on an extraction from single-transistor characteristics, is evaluated from simulated data using a sophisticated compact model and, where applicable, also device simulation. This approach allows the origin of observed inaccuracies or failures of certain methods to be identified. Second, the test structure-based methods are reviewed, and third, all methods were applied to experimental data. This paper and its results provide insight into each method's accuracy; its application limits with respect to a technology, a device size, and an operating range as well as its requirements in terms of equipment and extraction effort.