Radiation Effects of Double Layer Dielectric Films

Double layer dielectric films are examined for Si surface passivation in a radiation hardened Si device. The double layer dielectric films of Si3N4/SiO2 and PSG/SiO2 are shown to have lower sensitivity to ionizing radiation than a CVD-SiO2/SiO2 film named a double layer SiO2 film. However, the former two dielectric films show much larger initial interface state densities than the latter one. Effects of post oxidation annealing on the radiation induced interface states are also studied. The double layer SiO2 film is applied to realize an IIL device with a radiation tolerance of more than one Mrad(Si).