Atomic-scale defects associated with the negative bias temperature instability

We utilize magnetic resonance measurements to identify the fundamental atomic-scale defect structures involved in the negative bias temperature instability. In gate stacks composed of pure silicon dioxide, we find a degradation mechanism directly involving P _b0 and P _b1 defect centers (silicon dangling bond defects in which the silicon is back-bonded to three other silicon atoms precisely at the silicon/silicon dioxide interface). We observe that, in pure SiO₂-based devices, the generation of these interface defects is catalyzed by the generation of E′ center bulk dielectric defects (silicon dangling bond defects in which the silicon is back-bonded to oxygen atoms). These observations are the first to indicate a prominent role for E′ centers in the negative bias temperature instability for pure silicon dioxide-based devices. In gate stacks composed of plasma-nitrided oxides, we identify a degradation mechanism which is dominated by the generation of a new defect center which we identify as a K _N center. K _N centers are silicon dangling bond defects in which the silicon is back-bonded to three nitrogen atoms with second-nearest neighbor atoms likely including oxygen. K _N centers are located within the amorphous silicon oxy-nitride and electrically behave as both interface states as well as bulk dielectric defects (serve as both recombination and tunneling sites). In these plasma-nitrided gate stacks, the negative bias temperature instability does not involve the generation of P _b0, P _b1, or E′ centers. These collective observations provide a useful fundamental understanding with which to critically examine the current and future negative bias temperature instability framework.