Excellent passivation of ultrathin polysilicon passivating contacts using a single Al2O3 layer for hydrogenation

We demonstrated excellent surface passivation of ultrathin n-type doped polysilicon on both textured and polished n-Cz wafers. Effective carrier lifetimes of 6 ms for textured wafers and up to 15 ms for polished wafers were obtained. This was achieved by a hydrogenation process using a single thin Al
2
O
3
layer. Also for p-type doped ultrathin polysilicon layers, we obtained promising passivation results with carrier lifetime up to 2.5 ms. These highly transparent and passivating ultrathin polysilicon contacts enable the development of high-efficiency and temperature-stable bifacial cells.