Light-Induced Effect of a-Si Films Fabricated Using the Super Chamber

Abstract
The light-induced effect of a-Si films with low impurity concentrations fabricated in the super chamber was investigated. It was confirmed that a reduction of impurity reduces the light-induced effect over a range of more than 1018 cm-3 for oxygen. Furthermore, other factors come to have an influence on the light-induced effect in the low-impurity region. We believe that there are at least two types of light-induced defects, one related to impurities, which may be located below the midgap, and one related to structural properties, which may be located around the midgap. For a further reduction of the light-induced degradation in a-Si films, it is necessary to reduce the impurities in a-Si films and to suppress the creation of dangling bonds around the midgap.