An electro-thermal modeling of modern SiGe and Si bipolar transistor structures using TCAD Sentaurus Synopsys has been carried out. It has been shown that for SiGe heterojunction bipolar transistors, operating at high current density, the internal temperature is higher than for identical Si transistors. As a result a stronger degradation of the device parameters and electrical characteristics is observed.
The effects of neutron irradiation on both Si bipolar junction transistor (BJT) and SiGe heterojunction transistor (HBT) are investigated using Synopsys TCAD tool. The carrier lifetime degradation under irradiation models are included in the program. For SiGe HBT at fluences as high as 10**15 cm-2 the degradation of peak current gain is less than 40%, and the device maintains a peak current gain of 80 100 after 10**15 cm-2. The simulation results are in good agreement with experimental data.