Comparison of neutron irradiation effects on the electrical performances of SiGe HBT and Si BJT

The change of electrical performances of silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) and Si bipolar junction transistor (BJT) was studied as a function of reactor fast neutron radiation fluence. After neutron irradiation, the collector current Ic and the current gain β decrease, and the base current Ib increases generally for SiGe HBT. The higher the neutron irradiation fluence is, the larger Ib increases. For conventional Si BJT, Ic and Ib increase as well as β decreases much larger than SiGe HBT at the same fluence. It is shown that SiGe HBT has a larger anti-radiation threshold and better anti-radiation performance than Si BJT. The mechanism of performance changes induced by irradiation was preliminarily discussed.