Long-term reliability of high-performance SiGe:C heterojunction bipolar transistors

The reliability of high-performance SiGe:C HBTs was studied under mixed-mode stress conditions. We applied much longer stress-times than previous investigations and observed a not yet described saturation of the base current degradation with stress-time. This saturation behavior was integrated into an ageing function enabling improved prediction of HBT and RF circuit ageing during a 10 year life-time frame. Additionally, reverse stress tests confirmed also an increase of the baseemitter capacitance.