In Situ Gamma Irradiation Effects on 4H-SiC Bipolar Junction Transistors

Gamma irradiation effects have been investigated on 4H-SiC bipolar junction transistors, where the devices were exposed under different biasing regimes such as saturation, cut-off, active, reverse and zero bias. Since bipolar transistors can be affected by dose rate, three different dose rates were used during irradiation tests. Characterization was performed on the transistors, without irradiation but in-situ to avoid delays between irradiation and characterization. The study explores the relationship between biasing conditions and their impact on radiation-induced degradation of SiC BJT transistors. From these experiments it is clear that 4H-SiC bipolar transistors can withstand high gamma doses, in the worst case less than 22 % degradation of the current gain was seen for doses of up to 2 Mrad(Si).