System design and hot zone optimization of monocrystalline silicon directional solidification furnace for PV application

• A directional solidification furnace for monocrystalline silicon is designed with high productivity and low consumption in seeds.
• Computational model for melt convection and thermal transfer during directional solidification of silicon ingots was built.
• Control strategies for thermal/flow fields were determined for cone-shaped, constant crystal diameter, final ending growth.

A monocrystalline silicon directional solidification furnace is designed to increase the productivity and reduce the cost of seeds. In the newly designed furnace, the process is divided into three regions such as seeding, growth, and ending process and different control algorithms are proposed. A 2D transient model is also developed to investigate the capability of the control algorithms for three stages of the solidification process with cone-shaped, constant diameter, and final completing growth. Different control parameters for thermal and flow fields are studied and their impacts on melt flow, thermal field and solidification interface shape, subsequently quality of as grown crystal. Simulation results indicate that by appropriately adjusting the control parameters, optimal thermal and flow fields as well as interface shape can be achieved in the new directional solidification furnace.