Structural properties of the solidified-Al/regrown-Si structures of printed Al contacts on crystalline Si solar cells

Structural properties of the solidified-Al/regrown-Si structures of screen-printed aluminum contacts on a crystalline silicon solar cell have been studied by transmission electron microscopy (TEM). TEM results revealed that the solidified-Al/regrown-Si boundary is sharply defined except for the local silicon protrusion. A possible mechanism for forming the Si protrusion has been discussed. The results presented in this study suggested that the back-surface field (BSF) layer is the result of the regrown silicon, and the amount of the dissolved Si upon firing is responsible for the BSF thickness.