Novel design of superjunction structure in third-generation SiGe HBTs for high breakdown voltage

In order to enhance the breakdown voltage of third-generation SiGe HBTs at no expense of RF performance and current handling capability, the superjunction (SJ) structure is studied. It is shown that the depth of SJ should be designed carefully and cannot exceed 18% of the total width of collector-base space charge region. Furthermore, a novel double SJ layers structure with unequal depth is presented, which could effectively improve avalanche behavior with an increase 6.7% in BVCBO and 33.3% in BVCEO.