Electrical properties of nitride/oxide multilayered thin films

The alumina/SiN_x multilayered film showed increased dielectric breakdown voltage and decreased leakage current compared to single-layer thin films. As the number of silicon oxynitride layers in the multilayered film increased, the breakdown voltages increased and the leakage current decreased. The silicon oxynitride formation at the SiN_x/alumina interface was directly confirmed by XPS study. The silicon oxynitride formation at the SiN_x/alumina interface was indirectly supported by dielectric ratio calculation obtained by C-V measurements.; Silicon oxynitride films had a lower defect density than alumina and SiN_x films. The SASAS films had a lower defect density than alumina and SiN_x films as well. This lowered defect density of the SASAS film is regarded as a transformation of the surface of the SiN_x films into the silicon oxynitride film.; Due to the high energy band gap of the silicon oxynitride film and trap charges within the nitride and oxide layers, the energy band diagram are modified and the local electric field redistribution in the dielectrics are modeled. It was found that the local fields at each layer were reduced due to charge accumulation at the interfaces, except through the SiO_xN_y layer, which has a higher breakdown voltage and a lower trap density.; The decreased leakage current and increased breakdown voltage in the SiN_x/alumina multilayered film is due to the SiO_xN _y interlayer formation. The resistivity of alumina/SiN_x 5-layered film was lower compared to single-layer alumina and silicon nitride films and almost constant (1 × 1012 Ω-cm) up to the electric field of 5 MV/cm.; SASAS film did not have a smoother surface compared to SiN_x films. Therefore, surface roughness was not a factor for the increased dielectric strength of the multilayered films. There were no observed dielectric strength increase for the nitride/nitride, oxide/oxide multilayered films.