Reconsideration of Hydrogen-Related Degradation Mechanism in Gate Oxide

In this paper, we have investigated the correlation between released hydrogen from Si/SiO₂ interface and trap creation in bulk SiO₂. The key point of these experiments is that hydrogen release from the interface is performed without trap creation in bulk SiO₂ by injected hot carriers. Therefore, negative bias temperature (NBT) stress or substrate hot electron (SHE) stress was utilized to release hydrogen from Si/SiO₂ interface. As a result, SILC is clearly observed after low voltage NBT stress in pMOSFETs. In this stress condition, impact ionization at anode interface due to injected hot electrons was negligible. In the same way, SILC is also observed by applying SHE stress in nMOSFETs. In addition, the SILC is suppressed by decreasing released hydrogen using fluorine incorporation in both stress conditions. From these results, we inferred that the released hydrogen from Si/SiO₂ interface strongly correlates to the trap creation in gate oxides