Considerations for forward active mode reliability in an advanced hetero-junction bipolar transistor

The implementation of safe operating area (SOA) is discussed in this paper to quantify electrical, thermal, and Hot Carrier (HC) limits for a SiGe hetero-junction bipolar transistor (HBT) in a forward active mode. An electrical limit should be constructed to prevent an unexpected catastrophic failure at a circuit level considering impedance to the base node of HBTs simultaneously affected by current and voltage, unlike an individual HBT measured by parameter analyzers. Also, an investigation of the critical parameter degradation such as Beta is observed in a full range of active mode, calculating the maximum tolerable current, bias, and power relative to the performance of a HBT. We demonstrate the unique behavior of current dependence of Beta degradation by a simulation of impact ionization location and rate, accompanied by Kirk effect. In addition, we associate a 1/V_BC model for time-to-fail (TTF) extrapolated into the use condition compared to a conventional V_BC model.