Recovery behavior in negative bias temperature instability

We have studied the recovery behavior observed in negative bias temperature instability (NBTI) from the aspect of bulk hole traps. Using the maximum entropy method to analyze isochronal annealing data, we evaluated the contributions of bulk hole traps with energy level E_t to the initial threshold voltage shifts just after NBT stresses, ΔV_OTi(E_t). Their shapes are Gaussian-like depending on the NBT stress temperatures, and ΔV_OTi(E_t) can explain NBTI recovery behaviors as well as the universality. The validity of a previously proposed empirical function describing NBTI recovery curves was confirmed, and the physical meanings of that function were examined. This study proves the importance of hole detrapping events and sheds light on the NBTI recovery mechanism.