Experimental analysis of gate oxide degradation-existence of neutral trap precursor, single and multiple trap-assisted-tunneling for SILC mechanism

We investigated gate oxide degradation to focus on two topics, which were neutral trap generation and stress-induced leakage current (SILC). We show that the neutral traps were generated by hole injection during Fowler-Nordheim stressing. The experimental result shows the existence of neutral trap precursor. We also show that the relationship between the neutral trap density and the SILC was linear in 6.2 nm thick gate oxide and deviation from the linearity was observed in thicker oxide. The linearity in 6.2 nm thick oxide suggests that the neutral trap and the trap that cause the SILC were generated by the same mechanism. Meanwhile, the deviation from the linearity suggests the change in conduction mechanism of SILC, that is, single to multiple trap-assisted-tunneling.