Influence of a-Si: H / c-Si Interface Properties on Performance of Hetero-Junction Back Contact Si Solar Cells

29th European Photovoltaic Solar Energy Conference and Exhibition; 959-961
The purpose of this work is to investigate the passivation effect of hydrogenated amorphous silicon (a-Si:H) deposited on crystalline silicon (c-Si) by PECVD changing with a hydrogen dilution ratio and an applied RF power. We also applied this work to high efficiency Hetero-Junction Back Contact Si Solar Cells (HBC) cell. We evaluated the passivation quality of a-Si:H both on flat structure (100) and on textured structure (111) Cz wafer surface, where the minority career lifetime was measured by -PCD technique. The results show that the passivation ability on flat structure (100) surface had strong dependence on a H2/SiH4 ratio and a RF power, on the other hand, less dependence was shown on textured surface (111). The Transmission electron microscope (TEM) observation of a-Si:H demonstrates that crystal grains were formed in a-Si:H film for worse passivation. It was found that a-Si:H is more easily to crystallize on flat structure (100) surface than on textured surface (111). We utilized these findings to achieve 24.9% efficiency by HBC structure cell.