Comparative study of HBT ageing in a complementary SiGe:C BiCMOS technology

Abstract

Both npn- and pnp-SiGe HBT types of a complementary BiCMOS technology were consistently studied under mixed-mode and reverse stress conditions to check for any ageing mismatches. These were found to be more pronounced under forward than under reverse stress. Long-term stress-tests revealed a not yet described base current degradation “catching-up” under low current stress conditions. The resulting ageing parameters were put together into an ageing function for incorporation into HBT compact models.