Solar Energy Materials and Solar Cells, Vol.101, 123-130, 2012
Gettering improvements of minority-carrier lifetimes in solar grade silicon
The minority-carrier lifetime in p-type solar-grade silicon (SoG-Si) produced by Elkem Solar was investigated after different types of heat treatment. Two groups of samples differing by the as-grown lifetimes were exposed to internal and phosphorus gettering using constant and variable temperature processes. Optimal heat-treatment parameters for each group of samples were then identified which improved the minority-carrier lifetimes to values higher than the minimum value needed for solar cells. Phosphorus gettering using a variable temperature process enhanced in particular the lifetime within each group, increasing in certain cases the lifetime from 3 up to 81 mu s. (C) 2012 Elsevier B.V. All rights reserved.
Keywords:Solar grade silicon;Minority-carrier lifetime;Internal gettering;Phosphorus gettering;Release/diffusion model;Segregation model