Radiation Damage in npn Si Transistors due to High-Temperature Gamma Ray and 1-MeV Electron Irradiation

摘要

The degradation of npn Si transistors, subjected to y and 1-MeV electrons at different irradiation temperature and the same dose/fluence, is studied. For the 20℃ irradiation I_B increases remarkably, while I_C decreases for VBE above 0.6 V. The radiation-induced degradation becomes significantly smaller for higher exposure temperatures. For the 200℃ irradiation, I_B remains of the same order as before irradiation, while I_C is nearly identical. It is also noticed that h_(FE) for the 200℃ irradiation amounts to 82 % of the starting value. A broad distribution of hole trapping levels is observed in the base region for the 20℃ exposure, while an electron trap with energy level Ec - 0.18 eV and a broad DLTS signal around 150 K was found in the collector region. The hole capture levels in the base region are related to radiation damage at the Si-SiO_2 interface region. E~(BC)720 is associated with the vacancy-oxygen or A center, while a broad peak around 150 K is likely related to the divacancy. It is concluded that the induced radiation defects in the base and collector regions correlate well with the device degradation of npn the Si transistors.