Capacitance transient study of the influence of iron contamination on the electrical characteristics of silicon grain boundaries

摘要

The influence of iron contamination on the electrical characteristics of an interfacial grain boundary created by bonding two (110)/(100) silicon wafers was examined by a capacitance transient technique. Compared with the clean sample, iron contamination increases both the density of boundary states (by at least three times) and the zero-bias barrier height (by 70 meV), while dramatically reducing by two orders of magnitude the electron/hole capture cross-section ratio. These results suggest that a larger barrier will be sustained at the iron contaminated boundary under low injection condition, thereby enabling more effective minority carrier collection and associated enhanced recombination activity.