Low-cost solar grade silicon powder through iterative gettering of thermally treated porous silicon

Abstract The purity Metallurgical Grade Silicon powder (MG-Si) must be enhanced to increase their functionality for various applications. Therefore, we present in this work a new alternative approaches to purify the (MG-Si). This approach is based on an iterative gettering (IG) which consist to create a sacrificial porous silicon (PS) layer on the top surface of silicon grain, followed by rapid thermal processing (RTP) in an infrared furnace at 900 °C under O 2 ambient and then etched with diluted acids. Surface morphology and chemical composition of the treated samples were analyzed by scanning electronic microscopy (SEM), energy dispersive X-ray (EDAX) spectroscopy and inductively coupled plasma associated to Atomic emission spectroscopy (ICP-AES) analysis. The effect of the purification process on the optical properties of MG-Si was evaluated by the PL spectroscopy. The results indicate that Si powder purity was successfully recovered to become as high as 6 N purity.