In this paper niobium is characterized as a silicon contaminant. It is shown that niobium is a relatively slow diffuser, with an intermediate diffusivity between very slow diffusers such as molybdenum and fast diffusers such as iron. Niobium is found to be very effective as a recombination center, and in addition prone to surface segregation. In addition, niobium shows optical activation, but no thermal activation. Three deep levels are revealed in niobium contaminated silicon, plus an additional level observed in high contamination dose samples only. One of these levels is located very close to midgap, and consistently niobium was also found very effective in degrading the generation lifetime.
The Electrochemical Society
1 Oct 2010
Volume: 33 Issue: 11 Pages: 133-144