Radiation induced defects in bipolar power transistor. Influence of radiation energy

The results of a study on the radiation-induced defects in a bipolar power transistor exposed to electrons of different energies are reported. The devices have been irradiated with electron beams of energies ranging from 2.2 up to 8.6 MeV and different doses from 0.2 to 5 × 10^13 electrons/cm2 (0.8-25 kGy). DLTS measurements have been performed on the irradiated devices to identify the recombination centers introduced by the radiation treatment. The experimental results have been compared with those reported in the literature, taking into account that part of the energy of the electron beams is absorbed by the packaging of the device. The dependence of the defect generation rate on electron energy is described by a simple model that takes into account the contributions of both primary displaced atoms and secondary recoils.