An investigation was made of the influence of Fe contamination upon the minority carrier lifetimes of multi-crystalline silicon. The minority carrier lifetime was measured by using the microwave photoconductive decay method. The original bulk lifetime was about 30μs after passivation with iodine solution. After intentional Fe contamination, the bulk lifetime declined with increasing temperature. Fast cooling in air led to the formation of more interstitial Fe ([Fe]i). Slow cooling by control of the furnace temperature limited the formation of more [Fe]i, but led to the formation of precipitation. The data supported the idea that the minority carrier lifetime in multi-crystalline silicon depended mainly upon the distribution of Fe rather than upon the total amount. The favourable effect of [Fe]i gettering was discovered after conventional phosphorus diffusion, and the [Fe]i concentration remaining in the silicon wafer was acceptable for solar cell applications.

Influence of Fe Contamination on the Minority Carrier Lifetime of Multi-Crystalline Silicon. X.J.Meng, Z.Q.Ma, F.Li, C.Shen, Y.T.Yin, L.Zhao, Y.H.Li, F.Xu: Chinese Physics Letters, 2010, 27[7], 076101