Ion implanted metal wrap through silicon solar cells

Ion implanted emitters show reduced recombination leading to solar cells with better light collection and voltage[1]. Metal wrap through solar cells reduce shading losses and allow improved series resistance [2]. As such, the two technologies should be complementary. We present results for the first ion implanted metal wrap through cells built at Applied Materials. The cells show the expected improvement in current over baseline cells, and match the baseline voltage. Our MWT cells are limited by poor fill factor due to high series resistance. We see no difference in cell efficiency between process flows for which the hole drilling is done before texturing and before metallization, and no difference in via shunting. Our results show promise for the combination of ion implantation with MWT technology.