SIGE HETEROJUNCTION BIPOLAR TRANSISTOR WITH AN IMPROVED BREAKDOWN VOLTAGE-CUTOFF FREQUENCY PRODUCT

摘要

The product of the breakdown voltage (BVCEO) and the cutoff frequency (fT) of a SiGe heterojunction bipolar transistor (HBT) is increased beyond the Johnson limit by utilizing a doped region with a hollow core that extends down from the base to the heavily-doped buried collector region. The doped region and the buried collector region have opposite dopant types.