Influence of the substrate on the degradation of irradiated Si diodes

Abstract

Radiation damage in n+p and p+n Si diodes by 1 MeV fast neutrons and 1 to 2 MeV electrons is investigated as a function of the type of Si substrate and radiation source. The degradation of the electrical performance by irradiation increases with increasing fluence and is much larger for CZ-Si diodes than for FZ-Si diodes. The difference of radiation damage in diodes fabricated from different Si substrates is thought to be due to the formation of lattice defects which are associated with the creation of oxygen-related complexes. The degradation of diodes irradiated by neutrons is also larger than for electron-irradiated diodes. The damage is more pronounced as the acceleration voltage increases for electron irradiation. This is attributed to the different number of knock-on Si atoms and the nonionizing energy loss during irradiation.