2 PATHWAYS OF POSITIVE OXIDE-CHARGE BUILDUP DURING ELECTRON-TUNNELING INTO SILICON DIOXIDE FILM

Two positive oxide-charge generation pathways with low voltage or kinetic energy threshold in the Si-gate/SiO2/Si-substrate structure are correlated with experiments. They are initiated by Fowler-Nordheim electron tunneling through sub-10-nm SiO2. These tunneled electrons in the polycrystalline Si gate or crystalline Si substrate generate energetic holes by two collision mechanisms: interband impact generation and interband Auger recombination. The energetic holes are then back injected into the oxide valence band by surmounting the 4.25-eV Si/SiO2 hole barrier and captured by oxide hole traps. The calculated electron threshold energy to generate a positive oxide charge by the impact mechanism is E(C-SiO2) + 2.24 eV or E(C-Si) + 5.37 eV compared with 2.0 eV and 4.92+/-0.10 eV experimental data, and by the Auger mechanism, E(C-SiO2) + 0.0 eV or E(V-Si) + 4.25 eV compared with 4.25+/-0.26 eV experimental data.