Influencing Light and Elevated Temperature Induced Degradation and Surface-Related Degradation Kinetics in Float-Zone Silicon by Varying the Initial Sample State

摘要

Light and elevated temperature induced degradation (LeTID) kinetics in float-zone silicon are investigated by varying the initial sample state, composed of different base material, base doping, SiNx:H films, and subsequent firing, and/or annealing steps. The approach of deliberately changing the initial sample state is shown to allow for specific studies of influences of LeTID kinetics. Bulk- and surface-related degradations are examined separately and the influence on the kinetics of bulk- and surface-related degradation is illustrated by a four-state and three-state model, respectively. In case of bulk-related degradation, an increase in defect density because of the firing step is shown, whereas the annealing step has an inverse effect. Both temperature steps-individually and combined-influence the transition rates of bulk-related degradation and regeneration by presumably changing the distribution of a defect precursor. For surface-related degradation, the firing step reduces the transition rate from the initial to the degraded state. In addition, the influence of a comparably humid atmosphere and the absence of UV light are found to be negligible.