High efficiency large-area multi-crystalline silicon solar cells using reactive ion etching technique

Surface texturing is an essential process step in solar cell production for last decade. But for multi-crystalline Si, conventional chemical texturing using acidic solution could not make as low reflectance as mono-crystalline Si using alkaline solution, due to its random surface topography. In this work we demonstrated a large-area (156 × 156 mm) multi-crystalline silicon solar cell by maskless reactive ion etching (RIE) technique with extremely low reflectance of 2.1% in the weighted average (400-950 nm), which results in high short circuit current density of 35.65 mA/cm². The conversion efficiency of RIE-textured solar cell is 18.02% and has 0.51% absolute gain compared with chemical etched cell. By optimizing the anti-reflection coating layer, SiNx/SiO_x dual ARC is introduced to further improve the reflectance and conversion efficiency of 1.4% and 18.23% respectively. Detailed process and cell performance will be discussed based on surface texturing by RIE technology.