Dislocation Engineering in Multicrystalline Silicon

Dislocations are known to be among the most deleterious performance-limiting defects in multicrystalline silicon (mc-Si) based solar cells. In this work, we propose a method to remove dislocations based on a high temperature treatment. Dislocation density reductions of >95% are achieved in commercial ribbon silicon with a double-sided silicon nitride coating via high temperature annealing under ambient conditions. The dislocation density reduction follows temperature-dependent and time-dependent models developed by Kuhlmann et al. for the annealing of dislocations in face-centered cubic metals. It is believed that higher annealing temperatures (>1170°C) allow dislocation movement unconstrained by crystallographic glide planes, leading to pairwise dislocation annihilation within minutes.