A Generalized Reaction–Diffusion Model With Explicit H– H₂ Dynamics for Negative-Bias Temperature-Instability (NBTI) Degradation

In this paper, negative-bias temperature-instability (NBTI) modeling, based on a generalized reaction-diffusion framework, is presented. Unlike the previous models, the release of atomic hydrogen from the Si-H bonds at the Si/oxide interface and its subsequent conversion into molecular H2are considered without the (unphysical) assumption of instantaneous transition. The conversion reactions are handled explicitly with finite transition time and numerical solutions that contain both H and H2dynamics are obtained. The conversion reactions result in a distinct time behavior which cannot be predicted from either H- or H2-only simulations. The results are then explained analytically. The implications of hydrogen conversion dynamics on saturation of NBTI characteristics and device lifetimes are also discussed