[20p-133-1~14] 16.3 Bulk, thin-film and other silicon-based solar cells

▲ [20p-133-5] Controlling Solution Surface Tension for the Cleaning of Small Size Textured Si Surface to Obtain Extremely Low Surface Recombination Velocity of 0.6 cm/s

〇(PC)Cong Thanh Nguyen¹, Keisuke Ohdaira¹, Hideki Matsumura¹ (1.Japan Advanced Institute of Science and Technology (JAIST))

Keywords:MPAT process, Chemical cleaning of textures, Surface tension

Cleaning and passivation of small size textured crystalline silicon (c-Si) surface are always challenging owing to its complicated fine structure. In this work, we developed a novel chemical cleaning procedure suitable for such small size textured surface to obtain quality passivation with extremely low surface recombination velocity (SRV) of 0.6 cm/s. In this cleaning, we noticed an important role of controlling solution surface tension; hence we mixed methanol (CH₃OH) with hydrochloric acid (HF) to reduce its surface tension. Without mixing methanol with HF, SRV of only 3.5 cm/s was obtained. We named this finding “Methanol-Assisted Cleaning (MAC)” process. Features of the MAC process were also investigated, which is expected to be useful for cleaning of any kinds of Si wafers.