Effects of thermal budget in n-type bifacial solar cell fabrication processes on effective lifetime of crystalline silicon

The effects of residual C on cell properties are investigated from the view point of thermal budget in the n-type bifacial cell processes. Implied V-oc obtained from wafers with same O-i concentration depend on the thermal budgets decreases as the C-s concentration increases. The V-oc values vary depending on the wafer with different growth cooling rate. To analyze the effect of thermal budget correspond to solar cell fabrication process, CZ wafers with almost the same O-i concentrations are prepared. One of the wafers with relatively high residual C-s concentration shows the longer lifetime than the initial value after the 950 degrees C annealing step. On the other hand, the lifetime of a wafer with relatively low C-s concentration dramatically decreased by the same process due to the O segregation. These results suggest that it is important to choose appropriate wafer specification, starting with feedstock material, for increasing the solar cell efficiency. (C) 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).