The Effect of Phosphorus Gettering on Fine-Grained Multicrystalline Silicon

An analysis of the minority carrier lifetime of individual non-dislocated grains before and after phosphorus diffusion gettering suggests that smaller grains respond less to the gettering process than larger grains. The response is highest in the top and bottom positions of the ingot, since these positions are heavily polluted by the ingot red-zone. However, independently of position, there is a clear trend in the response decreasing approximately linearly with the smallest dimension of the grains. This can be related to increased influence from recombination active grain boundaries, which appear to affect the intragranular response up to 2mm from the boundary.