INFLUENCE OF THE SUBSTRATE ON THE DEGRADATION OF IRRADIATED SI DIODES

Radiation damage in n(+)p and p(+)n Si diodes by 1 MeV fast neutrons a nd 1 to 2 MeV electrons is investigated as a function of the type of S i substrate and radiation source. The degradation of the electrical pe rformance by irradiation increases with increasing fluence and is much larger for CZ-Si diodes than for FZ-Si diodes. The difference of radi ation damage in diodes fabricated from different Si substrates is thou ght to be due to the formation of lattice defects which are associated with the creation of oxygen-related complexes. The degradation of dio des irradiated by neutrons is also larger than for electron-irradiated diodes. The damage is more pronounced as the acceleration voltage inc reases for electron irradiation. This is attributed to the different n umber of knock-on Si atoms and the nonionizing energy loss during irra diation.