Two 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 EC-SiO2+2.24 eV or EC-Si+5.37 eV compared with 2.0 eV and 4.92±0.10 eV experimental data, and by the Auger mechanism, EC-SiO2+0.0 eV or EV-Si+4.25 eV compared with 4.25±0.26 eV experimental data.