Influence of Argon Gas Flow Rate on Oxygen and Carbon Impurities Concentration in Multicrystalline Silicon Grown by Directional Solidification Furnace: Numerical and Experimental Investigation

The quality of the multi-crystalline silicon ingot mainly depends on the defects and impurity distribution. The impurities originate from the various furnace parts and feedstock. The argon gas which acts as carrier gas plays an important role to reduce the chemical reaction inside the furnace. The reduction of carbon and oxygen concentration results in the reduction of SiO, CO and SiC formation. Various argon gas flow rates (5 LPM to 30 LPM) are simulated and C, O, CO and SiO concentrations were analysed. By increasing the argon gas flow rate, the SiO gas in the melt-free surface gets reduced from 6.9E2 to 5.1E1ppma. Also, it prevents CO gas formation in the melt-free surface. Oxygen concentration is lower than the concentration required for LID for 25 LPM and 30 LPM. From the 20 LPM, mc-Si ingot has Carbon concentration lower than the critical concentration required for SiC formation. The experimental result of 25 LPM Argon gas flow rate is compared with simulation results.