Processing Methods of Silicon to its Ingot: a Review

Any metal must be processed from its ore before employing it in various industrial applications; this is the similar case with Silicon (Si) as well. Occurring in the form of silicates in the earth’s crust, Si must be processed to achieve high purity for industrial applications. A major share of Si goes into the production of its wafers on which miniaturized circuits can be integrated and these wafers are also used in making solar cells. These wafers are produced by dividing Si chips into smaller parts, and the Si chips are produced by slicing Si ingots. Once the ingot is produced there is no scope to increase the purity of the Si, and the wafers will have purity less than or equal to the ingot purity and the solar cells produced will have equivalent conversion efficiency. Hence, the production of Si ingot plays a very crucial role at the back-end in determining the final purity of the wafer or efficiency of the solar cell. The pace at which the technology is developing today forecasts a huge demand of high purity Si wafers and alternate energy sources are also which in turn demands further increase in purity that makes the Si ingot production highly important. The present-day use of very large-scale integration techniques and the advancement towards the ultra-large-scale integration further makes Si chips foremost resourceful. The current review work aims to compile the capabilities of existing Si ingot production methods which are already employed in industries and production methods that are still being researched upon, and to present critical analysis which has been done to provide the method to be chosen to produce Si ingot based on application, production quality and quantity.