Investigating the changes of electrical characteristics of Bipolar Junction Transistors, before and after gamma irradiation

Bipolar junction transistors (BJTs) are active semiconductor devices commonly used for amplification and switching applications. In this study, transistors have been biased to operate in active region and by measuring the electrical characteristics of BJTs, the effect of gamma irradiation on each of these characteristics was investigated before and after the gamma irradiation by 60Co source. In order to measure the electrical characteristics, for each of the transistors under consideration, the appropriate circuit was designed. The experimental results show that by increasing the dose received by each transistor, the collector current decreases and collector-emitter voltage increases. So that the highest change in electrical characteristics of BD911 and 2N3420 transistors is observed after receiving the amount of 20kGy dose of gamma irradiation. On the other hand, doses of gamma radiation in the range of less than 1kGy does not have considerable effect on the electrical characteristics of BJT transistors. So, these transistors have the highest structure resistance against the gamma rays and can be used in designing electronic circuits used in radiant environments.