Analysis of the local extraction method of base and thermal resistance of bipolar transistors

This paper presents an extensive method to determine the extraction region were the method (published earlier) that consistently accounts for self-heating and Early effect to accurately extract both base and thermal resistance of bipolar junction transistors is applicable. The method is able to determine the lower and upper limits of the extraction region (i.e., a region with very small variations of the extracted base resistance) were the method yields correct results for the extracted base and thermal resistance. A generalization of the extraction method is developed that includes devices with very small Early voltage (V_A). The method is directly applicable to transistors, thus no dedicated test structures are need. The method is demonstrated on advanced industrial SiGe HBTs.