Electron irradiation effects on DC electrical performances of SiGe HBT in a comparison with SiBJT

The DC characteristics of SiGe HBT irradiated at different electron dose have been studied in a comparison with those of Si BJT. Generally, I(b) and I(b)-I(b0) increase, I(c), I(c)-I(c0) and its +/- transition V(be) as well as DC current gain beta decreases with increasing dose; increase of I(b)-I(b0) with increasing dose for Si BJT is much larger than that for SiGe HBT; beta increases with V(be) or I(b), but decreases at I(b) < 0.25 mA with I(b), and congregates at higher dose; and a damage factor d(beta) is much less at the same dose for SiGe HBT than for Si BJT. SiGe HBT has much better and-radiation performance than Si BJT. Some anomalous phenomena for increase of I(c), I(c)-I(c0), I(b)-I(b0) and beta at low dose have been found. Some electron traps have been measured. The mechanism of changes of characteristics is discussed.