Development of modified directional solidification furnance to grow high quality multi crystalline silicon ingots for photovoltaic application

Abstract

Numerical simulation is used to investigate directional solidification newline(DS) furnace for the growth of multi-crystalline silicon ingots. Thermal stress, newlinedislocation, and impurities significantly affect solar cell efficiency. Heat newlinetransport has an important role in the control of thermal stress and newlinedislocations. If we control the Thermal filed of the furnace we can achieve newlinequality of the mc-Silicon ingots. Impurities are originating from the furnace newlineparts. The m-c interface shape has a significantly effect on the quality of the newlinesilicon ingot during the crystal growth process. The impurity is easily newlineaccumulated near the central region when the interface is concave. The newlineconvex crystal-melt interface shape can push way impurities from centre to newlineouter region of the ingot. The thermal behaviour of the DS system is highly newlinenon-linear which can be investigated by using simulation tools. Numerical newlinesimulation is the best tool to understand DS process. From the numerical newlinesimulation results we can achieve the high quality mc-Si ingots with a newlineminimum of defects. In this thesis we have used 2D axi-symmertic model newlineCGSim package to study the thermal behaviour of the DS system, which is newlinebased on the Finite Volume Method (FVM). The numerical simulation is newlinemainly help to save the time and money. The experimental study are used by newlineDS furnace-G1, it is made by Hind High Vacuum (HHV). newline First chapter starts the brief introduction of the solar energy sources newlineand discusses the general background of solar cells. The different methods newlineinvolved in silicon growth process have been discussed. This chapter newlinediscusses the brief literature survey on directional solidification process and newlinethe effect of modified directional solidification furnace. And also, it newlineintroduces briefly wafer to cell making process. newline newline