A novel design methodology for breakdown voltage enhancement in the third-generation SiGe HBTs

In order to enhance the breakdown voltage of the third-generation SiGe HBTs for microwave power application, a novel design methodology of HBTs with superjunction structure is presented. Both the superjunction structure location and the concentration is optimized step by step to compromise the breakdown voltage (BVCBO and BVCEO) and high frequency characteristics. It is shown that the superjunction structure located inside the collector-base space charge region and with a moderate concentration (as well as twice of collector concentration) could effectively enhance the breakdown voltage with less expense of cutoff frequency. The design methodology will present a useful guideline of SiGe HBTs for microwave power application.