We investigated the influence of cooling rate on dislocation density in multicrystalline silicon using the unidirectional solidification process for solar cells. The results showed that the maximum value of dislocation density is decreased and that of residual stress is increased in a fast cooling process. These phenomena are attributed to the difference in dwell time at an elevated temperature for multiplication of dislocations. (C) 2010 Elsevier B.V. All rights reserved.