An analysis of 175 MeV Nickel ion irradiation and annealing effects on silicon NPN rf power transistors

In this study NPN rf power transistors were irradiated by 175 MeV Ni13+ ions in the dose range of 100 krad to 100 Mrad. Their characteristics such as excess base current (ΔIB = IBpost − IBpre), dc current gain (hFE), transconductance (gm) and collector-saturation current (ICSat) were studied before and after irradiation. The damage factor (K) for hFE was calculated using Messenger–Spratt relation. The base current (IB) was found to increase significantly after irradiation and in turn decreases the hFE. The gm and collector current (IC) in the saturation region (ICSat) were found to decrease with increase in radiation dose. The results obtained here were also compared with that obtained by 140 MeV Si10+ ions, 100 MeV F8+ ions, 95 MeV O7+ ions and 50 MeV Li3+ ions irradiation studies in the same dose ranges to understand the LET effects. The recovery in the I–V characteristics of irradiated NPN transistors were studied by isothermal and isochronal annealing methods.